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GE PROPRIETARY INFORMATION Safety Engineering Page 9.1

ERB/PDBD_Project Design Basis Document (05 Nov. 2004)

GE Energy

9. Safety Engineering

Page9.1 General ....................................................................................9.2

9.2 Hazardous Area Classification .................................................9.7

9.3 Building and Compartment Ventilation Design.......................9.19

9.4 System Vent Design...............................................................9.24

9.5 Gas and Chemical Storage and Distribution Systems............9.28

9.6 Provision and Control of Personnel Access ...........................9.32

9.7 Design of Emergency Eyewash / Shower Stations ................9.45

9.8 Design of Work Areas for Appropriate Noise Levels ..............9.50

9.9 Signs and Pipe Marking .........................................................9.51

9.10 Design of Lighting and Power ................................................9.56

9.11 Fire Protection........................................................................9.58

9.12 Reference Materials ...............................................................9.63

9.13 Review Documentation Deliverables......................................9.67

9.14 Revision Table........................................................................9.67


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GE DESIGN BASIS DOCUMENT ERB/PDBD_Project Design Basis Document (05 Nov. 2004)

9.1 General

This document details design requirements for personnel safety in the

permanent facility. The information provided herein describes good power

plant safety engineering practices.

Applicable National and Local safety regulations that require additional or

specialized equipment or designs beyond those described in the proposal shall

be included in the plant design or take precedence as required by law.

Similarly, if National or Local safety regulations, or Owner preference

requires additional safety studies and services to be performed, they may be

included as contract adjustments.

In cases where Country/Local practices and codes are determined to be

equivalent or more stringent than the practices and codes, cited in the GE

Safety Engineering DBD, these Country/Local practices and codes should be

referenced within the project specific Safety Summary Report.

9.1.1 Owners Responsibility

The Owner is responsible for providing a site free of hazardous material risks

to Personnel prior to project mobilization. This shall be addressed by

removal, disposal and/or treatment of pre-existing contaminated materials(e.g. soil, ground water, etc.) at the site.

9.1.2 Design Criteria Documentation

A site specific Safety Engineering Plan shall be submitted to GE Engineering

Review Board (ERB) prior to the reviews and shall address all of the elements

of this Safety Engineering section of the design basis document. It shal

describe how it to meet the requirements of the GE Design Basis Document

(DBD). This plan shall also include:

A tabulated summary of all of the potentially hazardous materials beingused in the construction and operation of the power plant including: type

of hazards, location (use and storage), and required PPE (Personal

Protective Equipment) including locations where PPE is required.

Requirement that specifications for procurement of the above materialshall include the requirement to provide MSDS (Material Safety Data

Sheets).


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Hazardous Area Classification Map for systems and equipment within the

scope of supply. This is required for the Initial Review.

Hazardous Area Classification Map for the entire site. It is important tobegin creating this map as soon as there is a tentative site layout since

hazardous areas will impact the final site layout. A preliminary site

hazardous area map shall be provided for the Progress Review.

Consolidated map of all ventilation intake and exhaust locations, and ventdischarge locations, including elevations.

A detailed listing of all codes and standards (including date issued) forsupply of equipment and construction of systems and facility, for example:

NFPA 101 Life Safety Code, 2000 or ANSI/ASME B31.3 Code for

Process Piping, 1999 (Not just ANSI, ASME, NFPA).

9.1.2.1 Project Specific Safety Summary Report Guidance

To help GE understand the design philosophy being used to address safety

issues associated with the specific project. A safety summary report is useful

to provide safety design philosophy information that is not readily called out

on the project design documents (e.g. why a pipe is sized a certain way) to GE

Suggested partner & A/E design relevant aspects for inclusion in the safety

engineering design basis document summary report.

Top-level narratives describing what safety aspects are addressed for theproject, including reference to compliance with customers technica

specification as well as regional, national, and local codes, standards and

regulations.

Hazardous Area Classification: methodology / assumptions used to createthe Hazardous Area Map(s) for the plant, what specific codes, standards

references, internal calculation done by hand or using software, etc.

Ventilation Design: for the Heating, Ventilation & Air ConditioningDesign (HVAC) describes the basis and methodology for the

determination of the ventilation rates in hazardous areas. GE HazardousArea Maps are based on equivalent outdoor ventilation as defined by

NFPA 497 for the United States and projects in other countries subscribing

to the NFPA approach or IEC 60079-10 for the European Union and

projects in other countries subscribing to the IEC approach.

Gas and Chemical Storage and Distribution Systems: asphyxiating &flammable gases design, including discussion related to prevention of


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above normal concentrations in confined space; plus automatic shut-off

provisions in event of emergency or major leak occurrence.

Gas and Chemical Storage Distribution Systems: storage of petroleum &chemical products design, including discussion related to containment of

minor/major spills; plus health & safety considerations from workplace

personnel exposure.

Gas and Chemical Storage Distribution Systems: fuel gas equipmentdesign, including discussion related to compliance to what specific codes

standards, and references that are used for the design.

Gas and Chemical Storage Distribution Systems: compressed gas design,

including discussion related to compliance to what specific codes

standards, and references that are used for the design.

Provisions and Control of Personnel Access: overall workplace personnel

protection provisions, including discussion related to fall heights &

protection, safe touch temperatures, security fencing, mechanical &

electrical equipment lockout provisions including discussion related to

compliance to what specific codes, standards, and references that are used

for the design.

Provision and Control of Personnel Access: mechanical & electricaguarding provisions, including discussion related to personnel access

workplace maintenance provisions and what specific codes, standards, andreferences that are used for the design.

Design of Emergency Eye Wash / Shower Stations: provide a summary

and a map of where all emergency eye wash and shower stations are

located throughout the plant, acknowledge that the site is meeting the

minimum requirements defined in this document for location and type.

Design of Work Areas for Appropriate Noise Levels: near field noise

compliance means, plus health & safety considerations from workplace

personnel exposure.

Design of Lighting and Power: lighting provisions and groundingprotection including discussion related to compliance to what specific

codes, standards, and references that are used for the design.

Fire Protection: design details, including discussion on which plant areasare covered by what type of fire protection / suppression, portable fire

extinguishers and locations and rating of fire rated walls; plus integration


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into hazardous area classification development and plant emergency egress

means.

9.1.3 Acronyms and Definitions of Key Terms

9.1.3.1 Acronyms

AE - Architect Engineer

BOP Balance of Plant

EN European Normative standard

EPC Entity responsible for Engineering / Procuring / Constructing the plant

GT Gas Turbine

GE DBD General Electric Design Basis Document

HRSG Heat Recovery Steam Generator

IEC International Electrotechnical Commission

LEL Lower Explosive Limit

MSDS Material Safety Data Sheet

PPE Personal Protective Equipment

PPM Parts Per Million

ST Steam Turbine

9.1.3.2 Definitions

Confined or Enclosed Spaces (extracted from OSHA 1910.146) means any

space that:

1. Is large enough and so configured that an employee can enter andperform assigned work; and

2. Has limited or restricted entry or exit (such as tanks, vessels, silos

storage bins, hoppers, vaults and pits); and


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3. Is not designed for continuous employee occupancy

Permit required confined space means a confined space that has one or more

of the following characteristics:

1. Contains or has the potential to contain a hazardous atmosphere (e.g. is

subject to the accumulation of toxic or flammable contaminants or has

an oxygen deficientatmosphere);

2. Contains a material that has the potential for engulfing an entrant (e.ggrain, sawdust, sand);

3. Has an internal configuration; in which an entrant could be trapped or

asphyxiated by inwardly converging walls or a floor that slopesdownward and tapers to a smaller cross section; or

4. Contains any other recognized serious safety or health hazard.


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9.2 Hazardous Area Classification

The Hazardous Area Classification evaluates all the locations within the

power plant and classifies them based on the potential existence of hazardous

properties due to the presence of flammable vapors, liquids, or gases, or

combustible concentrations of dust or fibers. This classification shall be done

in accordance to applicable standards. It is to be cautioned that Internationa

Standards and specific Country Standards may differ from the NFPA

Standards followed in the U.S.

To create a Hazardous Area Map for US projects refer to:

United States Codes and Standards

NFPA 70 National Electrical Code (NEC)

NFPA 497 Recommended Practice for the Classification of FlammableLiquids, Gases, or Vapors and of Hazardous Locations for Electrical

Installations in Chemical Process Areas

API 500 Recommended Practice for Classification of Locations forElectrical Installations At Petroleum Facilities Classified As Class 1,

Division 1 and Division 2

API 505 Recommended Practice for Classification of Locations forElectrical Installations At Petroleum Facilities Classified As Zone 0, Zone

1 and Zone 2

To create a Hazardous Area Map for European Union projects refer to:

European Codes and Standards

IEC / EN 60079-10 - Electrical Apparatus for Explosive Atmospheres -

Classification of Hazardous Areas

EN 1127-1 Explosion prevention and protection

94/9/EC, Directive 94/9/EC of the European Parliament and the Council of23 MARCH 1994 on the Approximation of the Laws of the Member

States Concerning Equipment and Protective Systems Intended for the Use

in Potentially Explosive Atmospheres. (ATEX)


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IP-15 Institute of Petroleum Area Classification Code for Petroleum

Installations (Part 15 of the Institute of Petroleum Model Code of Safe

Practice in the Petroleum Industry)

IGE SR 25 Hazardous Classification of Natural Gas Installations

This area classification shall include associated interconnections and

equipment designed by the AE/EPC as well as the GE supplied equipment

All interconnections and equipment with the potential to create a hazard shall

be clearly indicated on a comprehensive site map indicating size, location, and

elevation of the hazard created. Special consideration shall be made for

equipment not provided by the AE/EPC. The considerations for this

equipment shall include:

1. Ensuring equipment is rated for use as located (e.g. rated equipment ina hazardous area).

2. Identifying the hazardous area(s) it may create and ensuring that non-rated equipment (not suitable for hazardous zone) is not located within

these identified hazardous areas .

3. Ensuring that inlets to fan ventilated enclosures / compartments

cannot draw potentially hazardous atmospheres into the enclosure /

compartment.

NOTE: specific hazardous area dimensions listed in this document are based

on US Standards.

This classification should include, as a minimum, any of the items below that

are associated with the particular project:

Natural Gas: Gas Turbine Enclosure, Fuel Gas Module/Compartment,

Flow Metering Tube, Piping, Filter/Separator, Heater(s), Scrubber,

Pressure Reducing Station, Fuel Gas Booster Compressor, HRSG duct

burner or auxiliary Boiler.

Syn-gas (gas derived from coal or residuals): Syn-gas Compartment, Gas

Turbine Enclosure, piping, processing equipment.

Hydrogen: Generator, generator shaft seals, detraining enlargement vent,Collector Cab/Compartment, hydrogenstorage bottles, hydrogen manifold,

battery compartment/room, Load Compartment.

Liquid Fuel Vapor/Mist: Liquid fuel Module, Gas Turbine Enclosure,

piping, processing equipment, storage and drains tank(s).


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Lube Oil Vapor/Mist: Mist Eliminator discharge, high-pressure

piping/tubing, Accessory Module, Lube Oil Skids with Lift Oil.

Mechanical Connections (Non-Welded) in the above systems.

Ventilation exhausts or vent discharges for the above systems.

9.2.1 Hazardous Area Philosophy Document

A Hazardous Area philosophy document shall be created. It defines the

assumptions used to create the Hazardous Area Map. Each area of the

Hazardous Area Map shall have its own assumption criteria that includes, but

is not limited to, the following items:

Ventilation (e.g. air changes per hour / flow for area)

Hazardous gas / liquid vapor (e.g. natural gas, hydrogen)

Volume / quantity of release of gas / liquid vapor - this can be duringnormal modes of operation or during a credible failure scenario

Interconnection points (e.g. flanges, welds, compression fittings)

All areas should have dimensions in x, y, and z directions and / or defined

shape

Identification of compartments and components that are to be located inareas outside of Hazardous Areas.

9.2.2 Hazardous Area Map

The Hazardous Area Map is a pictorial representation of the hazardous areas

as defined in the philosophy documentation (9.2.1). A Hazardous Area is an

area with the potential to contain hazardous atmosphere due to the presence of

gas / liquid vapor / liquid mist at an ignitable concentration. The Hazardous

Area map is required to have the following features:

Plan and elevation views

Each area shall have dimensions in x, y, and z directions and / or definedshape

Approximate locations for all field installed pipe vents. The Hazardous

Area bubble can either be shown directly on the Hazardous Area Map or

its dimensions can be tabulated in an attachment.


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Restricted areas are those areas that must be isolated from potentially

hazardous leak sources. Items that are not rated for use in a Hazardous Area

must be in a Restricted Area. There shall not be any potential for a Hazardous

gas / liquid vapor to exist in a Restricted Area. Examples of Restricted Areas

include:

Compartment air inlets as defined in the Ventilation Design section of thisdocument

Areas where non-rated components external to the compartments arelocated (as a general rule external components are non-rated for use in a

Hazardous Area)

Any other areas that may reasonably be expected to include a source of

ignition (e.g. welding area).

Once the site Hazardous Area Map has been compiled, a review shall be

conducted to verify that the equipment located in the hazardous areas is

properly rated, and address any non-compliance issues. This may require

relocating either equipment that creates a hazard or the non-rated equipment,

or upgrading the components affected by the hazards.

Examples of different hazardous area map views can be seen in FIGURES 1, 2

and 3.


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FIGURE 1 SAMPLE: Isometric View of Accessory Module Hazardous

Areas Created During Normal Operation.

FIGURE 2 SAMPLE: End View of Accessory Module Hazardous

Areas Created at Gas Compartment Doors During Ventilation Shut

Down


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FIGURE 3 SAMPLE: Pipe Vent Termination With High Pressure Flow

of Gas Indicating Large Release Source.


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9.2.3 Design of Equipment Located in Hazardous Areas

For equipment located in a hazardous area,

Properly locate electrical wiring conduit seal fittings in the conduit runsper the NEC, and install the manufacturers recommended conduit sealer

in the fitting

Pressurize and vent electrical junction boxes that potentially contain arcing/ sparking devices.

9.2.4 Hazard Identification Reference

The tables and figures in this section provide a reference for potential areas

within the basic designs of a typical power plant that may be deemed

hazardous due to the potential for:

Gas / liquid vapor /liquid mist resulting in a fire/explosion

Chemical releases

Electrical energy release

Note: not all of the hazards listed above are required to be identified on a site

Hazardous Area Map as identified by NFPA or EN 60079-10 (IEC 79-10)Other hazards may need to be considered depending on the applicable codes

for example, hot surfaces.


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TABLE 1 Hazard Identification Reference associated with Figures 4, 5, and 6

Chemical Electrical Fire / Explosion

1 HRSG Duct Burner System X2 Exhaust Enclosure X

3 GT Turbine Compartment X

4 Liquid Fuel / Atomizing Air Module X

5 Gas Valve Module / Compartment X

6 Fuel Gas Performance & Start-Up Heaters X

7 Coalescing Filter / Separator X

8 Fuel Gas Scrubber X

9 Fuel Gas Pre-Heater X

10 Filter Separator X11 Gas Drain Tank X

12 GT False Start Drains Tank X

13 ST HPU Module (not shown) X

14 Generator X X

15 H2 Generator Bottle Storage & Manifold (not shown) X

16 Collector Cab X X

17 Collector Enclosure X

18 Generator Terminal Enclosure (GTE) X X

19 LCI & Excitation Module X20 Battery Room(s) GT (end of the PEECC), ST X X X

21 ST Electrical Room X X

22 Oil Filled Transformers X X

23 Switch Yard (not shown) X

24 Biofouling Chemicals X

25 Water Treatment Chemicals X

26 Waste Neutralization Tank X

27 Fuel Oil Storage Tank X

28 Fuel Gas Flow Metering Tube X

FIGURES 4, 5, and 6 are Hazard Identification Maps that identify where the

chemical, electrical, and fire / explosion hazards outlined in the above table

are located. These figures are representative of a typical Combined Cycle

power plant with 2 7FA Gas Turbines and a Steam Turbine, but elements

depicted can be applied to any plant.


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FIGURE 4 Chemical Hazard Identification Map.


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FIGURE 5 Electrical Component Hazard Identification Map.


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FIGURE 6 Fire / Explosion Hazard Identification Map.

The locations of potential Fire / Explosion hazards shown in this figure are for

reference only.. This figure does not meet the requirements of a Hazardous

Area Map as required by either the US NFPA requirements defined in NFPA

70 (NEC) and NFPA 497 or the European Union requirements as defined by

ATEX and EN 60079-10.


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TABLE 2 Additional Hazard Identification References (Not shown on Figures

4, 5, and 6)

Chemical Electrical Fire / Explosion

Generator Line Accessory Compartment (GLAC) X

Generator Neutral Accessory Compartment (GNAC) X

Switch Gear / Medium Voltage Cell X

GT Electrical Room / PEECC / TCC / MCC X X

Water Wash Skid X

Closed Cooling Water System (closed w/ antifreeze) X

Fuel Gas Shut of Valve and Vent Valve skid (SSOV) X


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9.3 Building and Compartment Ventilation Design

Building and compartment ventilation is defined as airflow through any

building or compartment of a power plant. GE uses a variety of compartment

ventilation methods: positive pressure (forced draft), negative pressure

(induced draft), and natural/convective.

Positive pressure occurs when air is pushed into the building or

compartment by ventilation fans, creating a higher pressure inside the

building or compartment than the ambient pressure.

Negative pressure occurs when air is drawn out of the building orcompartment by ventilation fans, creating a lower pressure inside of the

building or compartment than the ambient pressure.

Natural/convective ventilation is created by wind, temperature or gasdensity differentials that cause the air within the building or compartment

to move.

Ventilation air may enter a building or compartment through a variety of

inlets. An inlet is any opening into a building or compartment through which

air may enter. This includes, but is not limited to, ducts and damper covered

openings, doorways, windows that open, and easily opened access panels

The air drawn in through the inlet shall be safe air, which does not contain

hazards. Safe air is defined as:

Air with no significant contamination by flammable gasses or vapors thatmight be harmful to either the equipment or personnel (greater than 25%

LEL Lower Explosive Limit per US-NFPA and EU guidance). Note: US

requirement specifies not greater than 10% LEL for personnel exposure.

Air that is not significantly above the ambient air temperature.

Ventilation air exits from a building or compartment through exhaust outlet(s)

Precautions must be taken when establishing exhaust outlet locations if there

are potential hazards in the exhaust air from power plant buildings and

compartments. The potential for hazards in exhaust air is dependent upon

what is contained within the building or compartment being ventilated. For

example:

Buildings and compartments containing hot equipment, in excess of 60C

(140F), use the ventilation for cooling purposes; exposure to the elevated


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temperature of this exhaust air may potentially harm personnel or

equipment. Note: this may include steam.

Buildings or compartments containing parts of a fuel system have thepotential for fuel leaks from equipment and the piping system, which may

contaminate the ventilation air. The ventilation exhaust of each building

or compartment, along with the estimated potential concentration of fuel in

the ventilation duct, should be factored into the location/orientation of the

building or compartment exhaust outlet(s). The potential fuel sources

may include natural gas, syn-gas, liquid fuel vapor/mist, or other

alternative fuel source.

Buildings or compartments containing high-pressure oil lines have thepotential for lube oil mist or vapor to leak into the building or

compartment, which may contaminate the ventilation air. The ventilationexhaust of each building or compartment along with the estimated

potential concentration of lube oil vapor or mist in the duct should be

factored into the location/orientation of the building or compartment

exhaust outlet(s).

Buildings or compartments containing hydrogen system equipment or DCbatteries have the potential for hydrogen to accumulate in the building or

compartment, which may contaminate the ventilation air. The ventilation

exhaust of each building or compartment along with the estimated

potential concentration of hydrogen in the enclosed space should be

factored into the location/orientation of the building or compartmentexhaust outlet(s).

Buildings or compartments containing a CO2fire suppression system shallnot exhaust into an enclosed area that could present a personnel hazard.

For indoor installations, the compartment exhaust outlet(s) must be taken

outside the main building.

Buildings or compartments that serve as maintenance areas wherewelding, cutting or other fume producing processes take place shall not

circulate ventilation exhaust from those maintenance areas into the inlet

ventilation of other non-maintenance areas located within the same

building.

Turbine-Generators installed within buildings have additional ventilation

considerations. Each compartment placed inside of the building needs to be

evaluated for the requirements of both its inlet and exhaust air, for example:

When installing compartments within a building with the associatedventilation fans mounted external to the building, the location of the


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ventilation fan must be considered carefully with respect to the impact

created by this exhaust. (e.g. away from the face of the inlet filter house,

personnel access areas, non-rated equipment, etc.).

When installing compartments within a building with the ventilation fansmounted internal to the building, the location of the outlet duct termination

must be considered carefully with respect to the impact created by this

exhaust (e.g. away from the face of the inlet filter house, personnel access

areas, non-rated equipment, etc.).

Compartments with temperatures significantly above ambient should bereviewed for location of the ventilation exhaust outlet to ensure that the air

does not exhaust into personnel access areas or other ventilation inlets.

Also, impact on the overall building ventilation design must accommodate

the additional heat load if this exhaust air is released inside of the building,as some compartments may draw inlet air from inside of the building.

Note: For each project, the specific model of GE gas turbines and their

accessories must be reviewed since GE designs vary.

9.3.1 Design for Gas Turbine Compartment VentilationExhaust

Potential ventilation exhaust hazards include: high temperature and / or the

presence of any of the following in the ventilation exhaust: natural gas, syn-

gas, liquid fuel vapor, alternative fuel gas or vapor/mist, lube oil mist orvapor, and CO2. Refer to the project specific GE Gas Turbine Heating &

Ventilation Schematic (0426) for design requirements.

9.3.2 Design for Fuel Gas Module (Compartment) VentilationExhaust

Potential ventilation exhaust hazards include: high-temperature and / or the

presence of any of the following in the ventilation exhaust: natural gas

hydraulic oil vapor or mist, and CO2. Refer to the project specific GE Gas

Turbine Heating & Ventilation Schematic (0426) for design requirements.

9.3.3 Design for Generator and Collector Cab Ventilation

Potential ventilation exhaust hazards include: high-temperature and / or the

presence of any of the following in the ventilation exhaust: lube oil vapor or

mist and hydrogen (hydrogen generators only). Refer to GE Generator

Equipment Documentation for design requirements.


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For indoor installations of hydrogen generators, the building design must

prevent the accumulation of hydrogen either by natural or forced ventilation of

ceiling / roof high points. The ventilation flow capacity must be sized for

the maximum generation rate of hydrogen to preclude gas build-up.

9.3.4 Design for Load Compartment Ventilation (whenapplicable).

Potential exhaust hazards include: high-temperature and /or the presence of

hydrogen in the ventilation (when attached to hydrogen generators only)

Refer to the project specific GE Gas Turbine Heating & Ventilation Schematic

(0426) for design requirements.

For indoor installations with hydrogen generators, either the ventilation mustbe taken outside the building or the building design must prevent the

accumulation of hydrogen either by natural or forced ventilation of ceiling /

roof high points. The ventilation flow capacity must be sized for the

maximum generation rate of hydrogen to preclude gas build-up.

9.3.5 Design of Battery Room Ventilation

Hydrogen is the only potential exhaust hazard. Hydrogen evolution occurs

during battery charging. Battery locations include: the PEECC, steam turbine

UPS batteries, and plant facilities batteries.

Battery room design must prevent the accumulation of hydrogen by ventilation

of ceiling / roof high points. Irrespective of the type of ventilation used

(convection or forced), flow requirements must be sized for the maximum

generation rate of hydrogen. In the case of forced ventilation, the ventilation

system shall have a redundant fan system with a method for starting the back-

up fan if the primary fan should fail. A means for detecting hydrogen

accumulation may be required by local codes or standards.

9.3.6 Design for Liquid Fuel/Atomizing Air Compartment

Ventilation

Potential ventilation exhaust hazards include the presence of any of the

following in the ventilation exhaust: liquid fuel vapor / mist and CO2. Refer

to the project specific GE Gas Turbine Heating & Ventilation Schematic

(0426) for design requirements.


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9.3.7 Turbine-Generator Building

Potential exhaust hazards include: high-temperature, lube oil vapor / mist and

hydraulic fluid vapor / mist, fuel gases and liquid fuel vapor / mist (if Gas

Turbine is located indoors) and hydrogen (when hydrogen generator is

included).

The turbine building ventilation system design must consider the inlet and

outlet requirements under all potential modes of operation (e.g. minimum

allowable number of building fans in operation) and ambient conditions (e.g

cold winter or hot summer temperatures) to ensure that the individual

compartments / modules have sufficient ventilation to meet their safe

operating requirements.

Refer to GE DBD Mechanical Systems Documentation for general designrequirements.

9.3.8 Design for Control Room and Office Area Ventilation

Control Room and Office Areas are intended for continuous human

occupancy. These areas are not designed for hazardous air. Ventilation

design must draw air in from a safe area outside the building. The air must

be free from contaminant levels that could be harmful to human health.

When these areas are part of a building that has the potential to contain

hazardous air, there must be a separate ventilation system that draws in airfrom outside the building, and a slight positive pressure must be maintained

inside the office or control room areas.

9.3.9 Design for Exhaust Compartment Ventilation

Potential ventilation exhaust hazards include: high temperature and / or the

presence of CO2 in the ventilation exhaust. Refer to the project specific GE

Gas Turbine Heating & Ventilation Schematic (0426) for design requirements.


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9.4 System Vent Design

Vents are defined as piping or tubing that discharge to the atmosphere. Vent

lines can either be isolated by a manual or automatic valve, or be continuously

open. Common examples are vent lines connected to return lines, open

funnels, drains, tanks, chemical storage tanks, pressure relief valves, gas

turbine gas fuel stop-ratio valve cavity (P2) vents, valve stem packing leak-off

tubing, hydrogen casing purge, hydrogen scavenging, hydrogen detraining

enlargements, and stator cooling water system vents.

For all vents, the following must be shown on the P&ID:

Whether of not the vent is a source of hazardous release

What type of release it is

Reference to the Hazardous Area documentation for all vents that

create a hazardous area as defined in the Hazardous Area

Classification section of this document.

All hazardous vents shall be routed individually to a safe discharge area based

on the potential hazards. Potential areas to avoid are:

Personnel access ways (e.g. platforms, walkways)

Arcing & sparking devices

Maintenance areas (e.g. grinding, welding)

Designated smoking areas

Note: Information denoted in blue with square brackets [ ] in the below

sections refers to the European Union classification for hazardous area

designation using Zone and Group, which is different from the US Class

Division, Group system.

9.4.1 Fuel Gas Vents

All fuel gas vents shall be individually routed and discharged to a safe areaclear of all ventilation inlets, non-rated electrical devices, other potential

ignition sources (e.g. hot components, furnaces, etc.), and walkways /

personnel access areas. Occasional releases from a small vent of a known

volume (e.g. block and bleed vent valve) has a minimum Class I, Div 1, Group

D [Zone 1, Group IIA]1.5 m. (5 ft) spherical radius hazardous area inside of a

Class I, Div 2, Group D [Zone 2, Group IIA]3.0 m (10 ft) spherical radius

hazardous area around the vent terminus. Large releases will have a larger


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hazardous area based on the pressure and amount of gas released (e.g. gas

compartment/module strainer blow-down connection (FG2)). Pressure Relie

lines shall not be ganged with each other or any other vent lines. Do no

route fuel gas vents to any drains tanks.

Note: Follow ALL notes and recommendations found on the GE Fuel Gas

System Schematic (0422) for additional information on routing of field run

vents, this includes requirements for vent lines to be run individually

recommended vent discharge design per GEK 110743 and hazardous area

size/shape at the discharge of the vent.

9.4.2 Purge Vents

All purge vents shall be individually routed and discharged to a safe area clearof all ventilation inlets, non-rated electrical devices, other potential ignition

sources (e.g. hot components, furnaces, etc.), and walkways / personnel access

areas. Occasional releases from a small vent of known volume (e.g. block and

bleed vent valve) that are purging fuel gas piping has a minimum Class I, Div

1, Group D [Zone 1, Group IIA]1.5 m (5 ft) spherical radius hazardous area

inside of a Class I, Div 2, Group D [Zone 2, Group IIA]3.0 m (10 ft) spherical

radius hazardous area around the vent terminus.

Note: Follow ALL notes and recommendations found on the GE Purge Air

System Schematic (0477) for additional information on routing of field run

vents, this may include requirements for vent lines to be run separately,recommended vent discharge design per GEK 110743 and hazardous area

size/shape at the discharge of the vent.

9.4.3 Hydrogen Vents

All Hydrogen vents shall be individually routed to a safe area clear of all

ventilation inlets, non-rated electrical devices, other potential ignition sources

(e.g. hot components, furnaces, etc.), and walkways / personnel access areas

Occasional releases from a small vent of known volume has a minimum Class

I, Div 1, Group B [Zone 1, Group IIC]1.5 m (5 ft) spherical radius hazardous

area inside of a Class I, Div 2, Group B [Zone 2, Group IIC]3.0 m (10 ft)spherical radius hazardous area around the vent terminus (Note: this guidance

is per NFPA 497 and is superceded by any GE provided hazardous area

information). Pressure Relief lines shall NOT be ganged with each other or

any other vent lines.

Note: Follow ALL recommendations found on the GE Customer drawings

provided for the Generator Accessories (potentially Generator Gas System


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Installation Design Specification 357A2258 and Specification, BDE Vent

Piping 358A4741) for additional information on routing of field run vents, this

may include requirements for vent lines to be run separately, recommended

vent discharge design and hazardous area size/shape at the discharge of the

vent.

9.4.4 Lube Oil Vents

Lube oil mist and vapor shall be exhausted outside of the Turbine Building

Lube oil mist and vapors should be considered potentially hazardous and this

should be taken into account when locating the terminus of the lube oil

demister vent. The vent from the lube oil mist eliminator has a minimum

Class I, Div 2, Group D [Zone 2, Group IIA] 1.5 m (5 ft) spherical radius

hazardous area. Note: depending on the efficiency of the technology used foroil mist elimination, the concentration of oil released in parts per million

(ppm) of will vary. This may result in this area not requiring a hazardous

classification for oil.

Note: Follow ALL notes and recommendations found on the GE Lube Oi

System Schematic (Gas Turbine: 0416, and Steam Turbine VD01L) for

additional information on routing of field run vents, this may include

requirements for vent lines to be run separately and hazardous area size/shape

at the discharge of the vent.

9.4.5 Steam Vents

All Steam vents shall be routed to an area away from personnel access areas to

allow for safe release of the steam. Recommendations include locating

silencer and vent discharges away from any personnel access areas including

floors, platforms, ladders or stairs at a minimum of 6.0m (20 ft) horizontally

and 3.0 m (10 ft) vertically and situated in such a manner that the vents do not

direct steam towards stairs, ladders, walkways, platforms, maintenance areas

and/or heat detection devices.

9.4.6 Liquid Fuel Vents

All liquid fuel oil vents and open funnels shall be routed to a safe area clear of

all ventilation inlets, non-rated electrical devices, other potential ignition

sources (e.g. hot components, furnaces, etc.), and walkways / personnel access

areas. The vent from a liquid fuel oil storage / drains tank has a minimum

Class I, Div 2, Group D [Zone 2, Group IIA]0.5 m (0.5 ft) spherical radius

hazardous area. Note: Depending on the design of the piping to the liquid


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fuel False Start Drain Tank, this area can be larger based on the fail open

properties of the GE inline drain valves, which may allow the drain line to be

pressurized during GT operation.


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9.5 Gas and Chemical Storage and Distribution Systems

These sections address design requirements for chemical storage areas and

compressed gas storage areas. This section does not cover design standards

for bulk fuel storage; this is covered in the GE DBD Mechanical Systems

Documentation. Typical chemicals that need to be addressed include aqueous

ammonia, anhydrous ammonia, anionic and cationic resins, ethylene glycol,

phosphate ester (a.k.a. Fyrquel), fire suppression foam, propylene glycol

sodium hypochloride, sodium hydroxide, sodium sulfite/sulfate, sulfuric acid

and various water treatment chemicals. Compressed gases, which need to be

considered typically include: Nitrogen, Hydrogen, and Carbon Dioxide (CO2)

Storage areas for chemicals and compressed gases must be provided with

appropriate signs. Ventilation of chemical storage areas shall be inaccordance with OSHA 29 CFR 1910, NFPA, Uniform Fire Code and / or

applicable local requirements.

The location of chemical storage areas shall be shown on the appropriate

drawings including the General Arrangement, Plot Plan, and, for all areas

containing flammable/explosive liquids or gases, on the Hazardous Area Map.

9.5.1 Storage and Distribution of Gases

Compressed gas systems for power plants in general fit into the following gas

categories and uses:

Carbon Dioxide Generator purge and Fire Suppression

Compressed Air Instrument and Service air

Gas Fuel Fuel for Gas Turbine, auxboiler and / or HRSG

supplemental firing

Hydrogen Generator fill and makeup for cooling

Nitrogen HRSG / BOP equipment blanketing and various system

purges

These systems will be under high pressure and require careful considerations

during design, construction and operation. The systems and components shal

be designed in accordance with ASME Boiler and Pressure Vessel Code

Section VIII and ASME Power Piping Code 31.1. For European Community

Countries the local pressure code (or already mentioned ASME Code)

97/23/EC, the Pressure Equipment Directive (PED) and 87/404/EEC Simple

Pressure Vessels shall apply. Additionally all systems shall address container


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specifications; safety relief devices; design of piping, tubing and fittings

ventilation; and heating. Systems shall be tested and proved to be tight at

maximum operating pressure. Facilities design shall comply with OSHA

1910 Subpart M. Non-US projects shall conform to either the US Codes or

the national codes and standards specified by that country per contract

requirements. Proper ventilation is required for processing and storage areas

to mitigate any combustion and/or asphyxiation potential.

Each one of these systems may contain the following:

High pressure gas storage cylinders

High pressure safety relief devices

Gas pressure control valves

Compressors

Extensive runs of interconnecting piping

Storage and handling facilities

Gas venting requirement

In general equipment and cylinders should be protected against mechanical

damage. Racks should be provided or other means to hold them securely. Ful

bottles should be kept separately from empty bottles. Caution signs should

address depressurizing systems before disassembly. There should be loca

gauges for the technician to verify depressurization of the system. Cylinders

should be located where they will not be exposed to excessive heat. Outdoor

installations should include a roof for solar radiation protection.

Bulk storage facilities should be located in the plant yard away from the main

structure. Limited numbers of cylinders are acceptable in main building areas.

Safety shutoff valves between bulk hydrogen storage facilities and the

regulating valve manifold assembly is recommended per NFPA 850,

paragraph 5-7.1.

GE specification 357A2258, Generator gas System Design Specification

provides guidelines for the design and installation of CO2 and Hydrogen gassupply systems for Generator Applications.

Carbon dioxide (CO2), Hydrogen (H2), and Nitrogen (N2) shall be stored in an

outside area, inside an enclosure with forced or otherwise wellventilation, or

inside an enclosure that precludes the unrestricted entrance of personnel

Enclosed compressed gas storage areas shall be designed to address exposure

to potentially hazardous or asphyxiating atmospheres through adequate forced


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ventilation, gas monitoring and warning systems, or a design that precludes

entrance into the gas storage area. Compressed gas storage areas shall be

provided with means of securing cylinders.

CO2 used for generator purge gas must be stored indoors or in a compartment

that maintains a temperature above 10C (50F). Refer to GE Generator

Station Designers Handbook, C411 Document for specific project

requirements. If unventilated, this compartment should be sized to store the

CO2 bottles only and preclude the entry of personnel. Refer to GE DBD

Mechanical System Description for design requirements of storage area.

Hydrogen storage enclosures shall be well ventilated enclosure, as defined per

NFPA 497 for hydrogen storage, is one that has any 3 of the possible 5 sides

(4 walls and roof) open, that arrangement allows for ventilation equivalent to

the equipment being outdoors.

CO2storage used for Fire Suppression systems shall have signs / monitoring

of any pits into which the CO2 can settle that meet the recommendations of

NFPA 12.

9.5.2 Design Considerations for Gas Fuel ConditioningEquipment

The design of an outdoor installation shall include a risk assessment based on

the probability of a gas leak and the possible consequences to personnel safetyand equipment safety (e.g. Classification of Hazardous Locations published

by Institution of Chemical Engineers Rugby, Warwickshire England 1990

authored by AW Cox, FP Lees, and ML Ang or British Standard IGE SR 25

Hazardous Classification of Natural Gas Installations). All Gas Turbine

Steam Turbine, and Generator equipment is designed to be installed in a safe

area regardless of the hazards that equipment may generate. Refer to GE DBD

Mechanical System documentation for design requirements.

9.5.3 Chemical Storage

A variety of chemicals are used throughout the power plant. Each chemica

has specific requirements for safe handling, storage, and use.

The main chemicals in use are:

Acids for demineralizer regeneration, and demineralizer waste

neutralization, e.g. sulfuric acid


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Caustics for demineralizer regeneration and demineralizer waste

neutralization, e.g. sodium hydroxide

Biocides for circulating water system treatment, e.g. sodiumhypochlorite

Ammonia, phosphates and carbohydrazide for cycle water treatment

Refer to the chemicals MSDS for details. These requirements shall be taken

into consideration when designing various chemical storage areas

Additionally there may be National or Local requirements that will mandate

additional requirements be addressed for various chemicals. For example

Ammonia storage in the US must comply with 40 CFR 68: General Guidance

for Risk Management Programs. Chemical storage areas shall be provided

with secondary adequate containment sized per the specifications in the GE

DBD Environmental Engineering Systems Documentation. Materials used for

construction of containment areas and associated equipment shall be

compatible with the chemicals that will be stored in that area. Separate

containment areas shall be designed for incompatible chemicals (i.e. acids and

bases). Ventilation shall be provided as a means of controlling excessive

temperature build-up in storage areas. To comply with NFPA 497 and loca

fire codes, specific fire protection measures for storage of combustible and

flammable materials shall be addressed. Design specifications for systems

including storage and piping which use highly hazardous chemicals (as

defined by 29 CFR 1910.119 Appendix A, or other appropriate nationa

standards) - shall include safety measures such as interlocks, detectionsystems, and suppression systems. Additional requirements may apply to the

use of highly hazardous chemicals.


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9.6 Provision and Control of Personnel Access

9.6.1 Provision of Access to Work and Maintenance Areas

Safe access and working platforms shall be provided for all work and

maintenance areas. A stairway or ladder must be provided at all worker points

of access where there is a break in elevation of 0.5 m (19 in) or more, and no

ramp, runway, embankment, or personnel hoist is provided. Access via stairs

or ladders shall be provided for access from one structure level to another

where operations necessitate regular travel between levels, and for access to

operating platforms for any equipment that requires routine attention. Fixed

stairs or ladders shall also be provided where access to elevations occurs daily

or during each shift for such purposes as gauging, inspection, regular

maintenance, etc.

9.6.2 Design for Provision of Fall Protection

Areas and equipment with work/maintenance areas higher than 1.2 m (4 ft)

above grade, and for which permanent means of fall protection (e.g. standard

railings) are not feasible or are inappropriate, shall have a means of anchoring

a personnel fall protection system. Anchors to which personal fall arrest

equipment is attached shall be capable of supporting at least 2270 kg (5,000

lbs) per employee attached or meet the specific load requirements for anengineered fall arrestment system under OSHA 29 CFR 1910.66 or other

applicable codes / laws. The location of the anchorage point should also

consider hazards presented by obstructions in the potential fall path of the

employee. OSHA 29 CFR 1910.23.

9.6.3 Design of Platforms, Walkways, Stairways, and Ladders

The design of platforms, walkways, ladders, and stairways shall conform to

NFPA 101 and, OSHA 29 CFR 1910 for US projects. Non-US projects shal

conform to either the US codes or the national codes and standards specified

by that country per the contract requirements, such as EN Standards forEuropean Community Countries. Note: requirements for the European

Community are provided in blue and square brackets [ ] per the following

specifications: Pr-EN 12437-2, 3, 4, EN-131-2, EN 292-1, EN-292-2, EN 353-

1. These design requirements are to ensure safe and easy access to al

components and required access areas in a safe manner by personnel. Refer to

the GE DBD Civil / Structural System documentation for design requirements


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9.6.3.1 Platforms

Platforms shall be designed and installed in accordance with 29 CFR 1910.23

Platforms are designed to serve as a working space for persons elevated abovethe surrounding floor or ground, including balconies or walkways provided for

access to machinery and equipment. All platforms where a potential fall of

over 1.2 m (4 ft) [EN: 0.5 m.] can occur shall be guarded with a standard

guardrail system.

Standard guardrail systems shall consist of a top rail, intermediate rail, and

posts, and shall have a vertical height of 1.0 m (3.5 ft) [EN: 1.1 m]nomina

from upper surface of top rail to floor, platform, runway, or ramp level. The

top rail shall be smooth-surfaced throughout the length of the railing. The

intermediate rail shall be approximately halfway between the top rail and the

floor [EN: 0.5 m], platform, runway, or ramp. The ends of the rails shall nooverhang the terminal posts except where such overhang does not constitute a

projection hazard.

A standard toe-board shall be provided whenever the platform is located

above an area where people may pass or where objects may fall. The toe-

board shall be 100 mm (4 in) nominal in vertical height from its top edge to

the level of the floor, platform, runway, or ramp. It shall be securely fastened

in place and with not more than 6.4 mm (0.25 in) clearance above floor level

It may be made of any substantial material either solid or with openings not

over 25 mm (1 in) in greatest dimension.

Pipe railings, posts, top and intermediate railings shall be at least 38 mm (1.5

in) nominal diameter with posts spaced not more than 2.5 m (8 ft) on centers

[EN: 1.5 m]. The anchoring of posts and framing of members for railings of

all types shall be of such construction that the completed structure shall be

capable of withstanding a load of at least 90 kgs (200 lbs) applied in any

direction at any point on the top rail [EN: Note: Testing of Guard Rails

Horizontal deflection of handrail shall not exceed 30 mm when loaded for a

minute with a force equal of 300 N times the distance in meters between the

stanchions. The measurement must be done at the junction point between

stanchions and the handrail and repeated halfway between the posts].

Walking surfaces shall be nominally level. The slope of a walking surface in

the direction of travel shall not exceed 1 to 20 (1:20) unless the ramp

requirements of NFPA 101 are met. The slope perpendicular to the direction

of travel shall not exceed 1 to 48 (1:48). Abrupt changes in elevation of

walking surfaces shall not exceed 6.4 mm (0.25 in)[EN 4 mm]. Changes in

elevation exceeding 6.4 mm (0.25 in), but not exceeding 13 mm (0.5 in), shall


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platforms shall be provided for each 6.1 m (20 ft) of height. Each ladder

section shall be offset from adjacent sections. Where installation conditions

(even for a short, unbroken length) require that adjacent sections be offset,

landing platforms shall be provided at each offset. [EN: When a fixed ladder

exceeds 10 m. it shall be provided with a rest platform. Platforms shall be

provided not more than 6 m. apart. Recommended intermediate platform

length is 0.7 m]

All rungs shall have a minimum diameter of 19 mm (0.75 in) for metal

ladders. The distance between rungs, cleats, and steps shall not exceed 0.3 m

(12 in) [EN: between 0.25 and 0.3 m] and shall be uniform throughout the

length of the ladder. The minimum clear length of rungs or cleats shall be 0.4

m (16 in) [EN: between 0.4 and 0.6 m]. The rungs of an individual-rung

ladder shall be designed so that the foot cannot slide off the end "Climbing

side." On fixed ladders, the perpendicular distance from the centerline of therungs to the nearest permanent object on the climbing side of the ladder shall

be 0.91 m (3 ft) for a pitch of 76 degrees, and 0.76 m (30 in) for a pitch of 90

degrees. [EN: 0.65 m in front Climbing Side, 0.2 m back (0.15 m in case o

discontinuous objects)]. The distance from the centerline to the nearest

permanent object in back of the ladder shall not be less than 0.18 m (7 in)

except when unavoidable obstructions are present. The clearance in back of

each rung shall not be less than 0.1 m (4 in).

FIGURE 7 Rail Ladder with Bar Steel Rails and Round Steel Rungs (from

29 CFR 1910.27, Figure D)


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The step across distance from the nearest edge of the ladder to the nearest edge

of equipment or structure shall not be more than 0.30 m (12 in).

Protection against the risk of falling through ladder openings shall be providedby a hatch cover or by guardrails in combination with a swing gate (Note

chains are not sufficient to meet this requirement). If gates are utilized, they

shall provide both top and mid rail protection. The hatch cover shall move

upwards or horizontally and close automatically (e.g. by spring or gravity) not

hindering the passage of the user. Counterweighted hatch covers shall open a

minimum of 60 degrees from the horizontal. There shall be no protruding

potential hazards within 0.61 m (24 in) of the centerline of rungs or cleats

The relationship of a fixed ladder to an acceptable counterweighted hatch

cover is illustrated in FIGURE 8. [EN: Exit in the platform; Trap doors

Protection against the risk of falling through such an opening shall be

provided by a trap door or by guard-rails in combination with gate. The trapdoor shall move upwards or horizontally and close automatically (e.g. by

spring or gravity) not hindering the passage of the user.]

FIGURE 8 - Relationship of Fixed Ladder to a Safe Access Hatch (29 CFR

-


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9.6.3.4 Ladder Cages or Wells

Ladders, cages, and wells shall be designed and installed in accordance with

29 CFR 1910.27.

All fixed ladders of more than 3.7 m (12 ft) shall be provided with cages

[EN: ladders of more than 3 m or the distance from the center of the ladder to

the unprotected side of a platform (or similar) is less than 3 m, then an anti-

fall device (such as a safety cage or a guided type fall arrester on rigid line)

shall be provided].

Cages shall extend a minimum of 1.1m (3.5 ft) above the top of landing [EN

1.1 m], unless other acceptable protection is provided.

Cages shall extend down the ladder to a point not less than 2.1 m (7 ft) normore than 2.4 m (8 ft) above the base of the ladder [EN: between 2.5 and 3

m], with bottom flared not less than 0.1 m (4 in), or portion of cage opposite

ladder shall be carried to the base.

Ladder cages shall have a clear width of at least 0.38 m (15 in) measured each

way from the centerline of the ladder [EN: Cage diameter shall be between 0.7

and 0.8 m]. Smooth-walled wells shall be a minimum of 0.7 m (27 in) from

the centerline of rungs to the well wall on the climbing side of the ladder

Where other obstructions on the climbing side of the ladder exist, there shall

be a minimum of 0.8 m (30 in) from the centerline of the rungs.

The spacing between vertical bars on the cage shall not exceed 0.24 m (9.5 in)

[EN: The spacing of safety cages shall be designed so that the empty spaces

are not more than 0.42 m2whereby the horizontal width of these space shall

not exceed 0.3 m].

When ladders provide access to landings that measure 1.2 m (48 in) or less

from the ladder rungs to the platforms guardrails, special means shall be used

to prevent personnel from falling over the guardrail. (See FIGURE 9)


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9.6.4 Emergency Egress

All buildings and structures designed for human occupancy shall be provided

with exits sufficient to permit the prompt escape of occupants in case of fire or

other emergency. Every building or structure shall be provided with exits of

the kind, number, location, and capacity appropriate to the individual building

or structure, with due regard to the character of the occupancy, the number of

persons exposed, the fire protection available, and the height and type of

construction of the building or structure, to afford all occupants convenient

facilities for escape.

The design of exits and other safeguards shall be such that reliance for safety

to life in case of fire or other emergency will not depend solely on any singlesafeguard. Additional safeguards shall be provided for life safety in case any

single safeguard is ineffective due to a human or mechanical failure.

Exits shall be arranged and maintained to provide free and unobstructed egress

from all parts of the occupied building or structure at all times. Every building

or structure, section, or area meant for human occupancy shall have at least

two means of egress remote from each other and arranged to minimize any

FIGURE 9 Special Means for Guarding Ladders Ending on

Platforms (29 CFR 1910.27 Figure D-9)


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possibility that any one fire or other emergency condition may block both

Exits and means of egress shall comply with the requirements of 29 CFR

1910.37 for US projects. Under US code, a single means of egress is

permitted for Special Purpose industrial occupancies from a story of section

in low or ordinary hazard industrial occupancies (e.g. the interior of a GE or

fuel handling enclosure is a high hazard area) where the distance to the exit

does not exceed 15 m (50 ft). Non-US projects shall conform to either the US

codes or the national codes and standards specified by that country per the

contract requirements, for European Community Countries IEC 60364.

9.6.5 Access and Working Space around Power GenerationEquipment

Sufficient access and working space shall be provided and maintained aroundelectric equipment to permit safe operation and maintenance of such

equipment in accordance with 29 CFR 1910.269.

Note: Guidelines for the dimensions of access and working space around

electric equipment in generating stations are contained in American National

Standard - National Electrical Safety Code, ANSI C2-1987 and in NFPA 70

National Electrical Code.

9.6.6 Access, Limiting Access, and Providing Sufficient Work

Space Around High and Low Voltage AreasNote: The below information is extracted from NFPA 70 Nationa

Electrical Code. This information shall be used for US projects. Non-US

projects shall conform to either the US codes or the national codes and

standards specified by that country per the contract requirements. For

European Community IEC 60364 is to be utilized.

9.6.6.1 Low Voltage (< 600 V)

At least one entrance of sufficient area shall be provided to gain access to the

working space around electrically energized equipment. For equipment rated1200 amps or more, and over 1.8 m (6 ft) wide, that contain over current

devices, switching devices, or control devices, there shall be one entrance to

the required working space not less than 0.6 m (24 in) wide and 2.0 m (6.5 ft)

high at each end of the working space. Any doors shall open in the direction

of egress and be equipped with panic bars, pressure plates, or other devices

that are normally latched but open under simple pressure. A single entrance

shall be permitted if :


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a) the location permits a continuous and unobstructed way of exit travel (e.g.away from the equipment), or

b) the depth of the workspace is twice that shown in TABLE 3 and thedistance from the entrance to the nearest edge of the equipment is not less

that shown in Table 3 for the voltage and condition applicable to the

equipment.

The minimum headroom of working spaces around service equipment,

switchboards, panel-boards, or motor control centers shall be 2.0 m (6.5 ft)

Where the electrical equipment exceeds 2.0 m (6.5 ft) in height, the minimum

headroom shall not be less than the height of the equipment.

Live parts of electric equipment operating at 50 volts or more shall be guarded

against accidental contact. Acceptable guards include approved enclosures(e.g. NEMA enclosures); limited access rooms or vaults; suitable

permanent, substantial partitions or screens with limited access; location on a

gallery, balcony, or platform elevated and restricted so as to exclude

unauthorized personnel; or an elevation of more than 2.5 m (8 ft) above the

floor or other working surface.

The working space for equipment operating at 600 volts nominal, or less to

ground, and likely to require examination, adjustment, servicing, or

maintenance while energized may not be less than indicated in TABLE 3. The

workspace shall be adequate to permit at least a 90-degree opening of doors or

hinged panels. In addition to the dimensions shown in TABLE 3, the workingspace in front of electrical equipment shall be the width of the equipment or

0.76 m (30 in), whichever is greater. Distances shall be measured from the

exposed live parts, or from the enclosure or opening if the live parts are

enclosed. Working space is not required behind or on the sides of assemblies

such as dead-front switchboards or motor control centers, where al

connections or renewable or adjustable parts, such as fuses or switches, are

accessible from locations other than the back or sides. Where rear access is

required to work on nonelectrical parts on the back of enclosed equipment, a

minimum horizontal workspace of 0.76 m (30 in) shall be provided.

Switchboards, panelboards, distribution boards, and motor control centersshall be located in dedicated spaces and protected from damage. For indoor

locations, this space is equal to the width and depth of the equipment and

extends from the floor to a height of 1.8 m (6 ft) above the equipment or to the

structural ceiling, whichever is lower. No piping, ducts, leak protection

apparatus, or other equipment foreign to the electrical installation shall be

located in this zone.


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TABLE 3 Working Spaces

Minimum clear distance [mm(ft)]

Nominal

voltage to

ground

Condition

(a)

Condition

(b)

Condition

(c)

0-150 900 mm (3 ft) 900 mm (3 ft) 900 mm (3 ft)

151-600 900 mm (3 ft) 1 m (3.5 ft) 1.2 m (4 ft

Conditions (a), (b), and (c), are as follows:

(a) Exposed live parts on one side and no live or grounded parts on the otherside of the working space, or exposed live parts on both sides effectively

guarded by suitable wood or other insulating materials.

(b) Exposed live parts on one side and grounded parts on the other side.

Concrete, brick, or tile walls shall be considered grounded

(c) Exposed live parts on both sides of the workspace [not guarded as

provided in Condition (a)] with the operator between.

Note: this table is taken from the 2005 version of the NEC article 110, table

110.26(a)(1).

9.6.6.2 High Voltage (> 600V)

Buildings, rooms, or enclosures containing exposed live parts or exposed

conductors operating at over 600 volts, nominal, shall be equipped with a

means of preventing access. A wall, screen, or fence shall be used to enclose

outdoor electrical installations to deter access by unqualified persons. A fence

shall not be less than 2.1 m (7 ft) in height or a combination of 1.8 m (6 ft) or

more of fence and a 0.30 m (12in) extension utilizing three or more strands of

barbed wire or equivalent. At least one entrance not less than 0.61 m (24 in)

wide and 2.0 m (6.5 ft) high shall be provided to give access to the working

space about electric equipment. On switchboard and control panels exceeding1.6 m (6 ft) in width, there shall be one entrance at each end of the equipment

A single entrance shall be permitted if

a) the location permits a continuous and unobstructed way of exit travel

(e.g. away from the equipment), or


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b) the depth of the workspace is twice that shown in TABLE 4 and thedistance from the entrance to the nearest edge of the equipment is not

less that shown in TABLE 4 for the voltage and condition applicable to

the equipment. Where bare energized parts (at any voltage) or

insulated energized parts (above 600 volts) are located adjacent to the

entrance, they shall be suitably guarded with a partition, screen, or

other barrier against accidental contact. Entrances shall be equipped

with a means of locking

Sufficient space shall be provided and maintained around electrical equipment

to permit safe operation and maintenance of equipment. The minimum

headroom and working space width is the same as defined above for systems

energized to 600 volts or less. The working space depth shall be as required in

TABLE 4. The workspace shall be adequate to permit at least a 90-degree

opening of doors or hinged panels. The minimum clear working space in fron

of electric equipment such as switchboards, control panels, switches, circuit

breakers, motor controllers, relays, and similar equipment may not be less than

specified in TABLE 4 unless otherwise specified in this section. Distances

shall be measured from the exposed live parts or from the enclosure or

opening, if the live parts are enclosed. However, working space is no

required behind equipment such as dead front switchboards or contro

assemblies where there are no renewable or adjustable parts (such as fuses or

switches) on the back and where all connections are accessible from locations

other than the back. Where rear access is required to work on de-energized

parts on the back of enclosed equipment, a minimum working space of 0.75 m(30 in) horizontally shall be provided.

TABLE 4 Minimum Depth of Clear Working Space At Electrical Equipment

Minimum Depth of Clear Working Space [mm (ft)]

Nominal voltage

to ground

Condition

(a)

Condition

(b)

Condition

(c)

601 to 2,500 900 mm (3 ft) 1.2 m (4 ft) 1.5 m (5 ft)

2,501 to 9,000 1.2 m (4 ft) 1.5 m (5 ft) 1.8 m (6 ft)

9,001 to 25,000 1.5 m (5 ft) 1.8 m (6 ft) 2.8 m (9 ft)

25,001 to 75kV 1.8 m (6 ft) 2.5 m (8 ft) 3.0 m (10 ft)

Above 75kV 2.5 m (8 ft) 3.0 m (10 ft) 3.7 m (12 ft)


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Conditions (a), (b), and (c) are as follows:

(a) Exposed live parts on one side and no live or grounded parts on the other

side of the working space, or exposed live parts on both sides effectivelyguarded by suitable wood or other insulating materials.

(b) Exposed live parts on one side and grounded parts on the other side.

Concrete, brick, or tile walls will be considered as grounded surfaces.

(c) Exposed live parts on both sides of the workspace (not guarded as

provided in Condition (a)) with the operator between.


110.34(A).

Unguarded live parts located above the working space shall be maintained at

elevations not less than specified in TABLE 5.

TABLE 5 - Elevation of Unguarded Energized Parts Above Working Space

Nominal voltage

between phasesMinimum elevation

601 to 7,500 2.8 m (9 ft)

7,501 to 35,000 2.9 m (9.5 ft)

Over 35kV 2.9 m (9.5 ft) + 9.5 mm (0.37 in) per kV above

35kV.


110.34(E)

9.6.7 Design for Safe Touch Temperature of Equipment

Maximum surface temperature exceeding 60C (140F) per ASTM C 1055 /

EN 563 within the power plant shall be guarded, covered, or equipped with a

means to prevent accidental contact where personnel are likely to be in close

proximity. Alternative protection can be provided to limit personnel access to

high temperature areas with standoff systems or other means of preventingaccess. Refer to GE DBD Mechanical System for design requirements.

9.6.8 Design for appropriate Equipment Guarding

Appropriate OSHA compliant guards shall be provided to protect personnel in

the power plant from all exposed hazardous surfaces, e.g. rotating, pinch


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point, electrical, and hot temperatures. Refer to OSHA 29 CFR 1910 Subpart

O, Machinery and Machine Guarding, for requirements. For projects in

Europe, refer to EN-292 The Machinery Directive

9.6.9 Design to Accept Locks (Control of Hazardous EnergyMechanical and Electrical)

All energy isolating devices shall be designed to accept a lockout device. An

energy-isolating device is capable of being locked out if it has a hasp or other

means of attachment to which, or through which, a lock can be affixed, or it

has a built-in locking mechanism. Energy isolating devices are defined as any

mechanical device that physically prevents the transmission or release of

energy, including but not limited to the following:

A manually operated electrical circuit breaker

A disconnect switch

A manually operated switch by which the conductors of a circuit can

be disconnected from all ungrounded supply conductors, and, in

addition, no pole can be operated independently

A line valve

A block

Any similar device used to block or isolate energy

Refer to 29 CFR 1910.147 for design requirements.

9.6.10 Design of Security Fencing

Appropriate security fencing shall be provided to restrict access of personnel

and the public to potentially hazardous power plant equipment (e.g

switchyards) Refer to GE DBD Civil/Structural System for design

requirements of the Security Fencing.


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9.7 Design of Emergency Eyewash / Shower Stations

The installation of emergency safety showers and eyewash fountains are

required in locations where personnel may contact chemical, biological, or

physical agents that require emergency washing facilities. Eyewash and

shower equipment for the emergency treatment of the eyes or body of a person

exposed to injurious materials shall meet the minimum performance

requirements outlined below in the General Requirements for Emergency

Eyewashes / Sowers. Emergency eyewash and shower stations shall mee

ANSI Z358.1.

9.7.1 General Requirements for Emergency Eyewashes/Showers

Provide in accordance with TABLE 6.

Provide eyewash units in any area where there is a potential for the eyes to

be exposed to corrosive, irritating, or toxic chemicals, biological hazards,

or physical hazards, such as chips or dust from sanding or grinding

processes.

Connect showers and eyewash units to potable water.

Specific water temperature ranges are not specified by regulation.Coordinate with client to determine desired water temperature.

Heat tracing shall be provided for outdoor installations with ambient

temperatures below 0C (32F) to prevent freezing of piping and

equipment.

Emergency showers and eyewash units shall be accessible within 10seconds at walking speed from the potential exposure source. Do not

locate in rooms or areas with lockable doors.

The water supply to shower and/or shower/eyewash combination units

shall be controlled by a shutoff valve, which is visible and accessible forshower testing or maintenance personnel in the event of leaking or failed

showerhead valves.

Definitions of the different types of emergency eyewash and shower units used

in TABLE 6:

Combination Shower and Eyewash unit*consisting of schedule 80 hot

dipped galvanized steel, chrome plated bronze stay open ball valves with


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chrome plated ball, stainless steel actuators and actuation graphics, ABS

plastic shower head delivering a minimum 500 mm (20 in) diameter

pattern to the target are 1.5 m (5 ft) above standing level, ABS plastic dual

stream head with ABS plastic float off covers secured with stainless steel

bead chains, self adjusting 0.5 lb/sec (8.0 gpm) eye/face wash regulator

assuring a constant, even flow under varying hydraulic conditions.

Self-contained, Gravity Feed Eyewash unit**with retractable trayprotecting eyewash heads, pinch valve design to ensure positive water

flow within one second of activation.

Eyewash / Body Wash unit*** consisting of piping which is hot dip

schedule 80 steel drain/pedestal mount, 12 mm (0.5 in) chrome plated

bronze stay open ball valve with chrome plated ball and stainless steel

push plate with actuation graphic, ABS plastic dual stream head with ABS

float off covers secured with stainless steel bead chain, self adjusting 0.22

lb/sec (3.5 gpm) regulator assuring a constant, even flow under varying

hydraulic conditions, ABS plastic bowl or stainless steel bowl.


47/67



TABLE 6 - Emergency Eyewash / Shower

System Equipment

Or Location

Chemical(s) Wash Station

Boiler Chemical Feed HRSG Phosphate

(pH control, corrosioninhibitor, remove hardness)

Combination Shower andEyewash *

Selective CatalyticReduction (SCR)

Ammonia StorageTank and Injection

Skid

HRSG 19% Aqueous Ammonia Eyewash / Body Wash

***

Circulating CoolingWater Chemical Feed

Cooling Tower Sodium Hypochlorite

Sulfuric Acid, Inhibitor

And Sulfite


Once-through Cooling Intake Structure Sodium Hypochlorite

(Reduce Biological Fouling)

Self-contained, Gravity FeeEyewash **

ST-G Bldg(Surface Condenser

Outlet)

Sodium Sulfite(Reduce Residual Chlorine)

Utilize Station forCondensate Chemical

Feed *

Raw Water ChemicalFeed (if provided)

Raw Water StorageTank

Sodium Hypochlorite Eyewash / Body Wash

***

Condensate ChemicalFeed

ST-G Bldg Oxygen Scavenger andAmmonia


DC Power Supply GT-G PEECCBatteries

Battery Electrolyte

(e.g. Sulfuric Acid)

Personal Eyewash Station(Saline Solution in Bottles

At Battery CompartmentLevel and CombinationShower and Eyewash

Base * of Access Stairs

ST-G Bldg

Battery Room

Battery Electrolyte

(e.g. Sulfuric Acid)

Eyewash / Body Wash

***

Steam WaterSampling and

Analysis Panel

ST-G Bldg

Ground Floor

Testing Chemicals Personal Eyewash

Station (Saline Solution inBottles)

Water TestingLaboratory (if

provided)

ST-G Bldg

Ground Floor

Testing Chemicals Eyewash / Body Wash

***

ST HPU ST-G Bldg

Ground Floor

Fyrquel (Phosphate Ester) Eyewash / Body Wash

***

Fuel Oil Treatment (ifprovided)

Fuel Oil Storage Area Magnesium Sulfinate(Vanadium Fuels),

Hytec 580 made by EthylCorporation

(Lubricity Additive for LightFuels Kerosene, Naphtha)

Self Contained, Gravity FeeEyewash **

Water Treatment Water Treatment Bldg Acid / Caustic storage Combination Shower andEyewash *


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9.7.2 Permanent Emergency Showers

Emergency showers shall be designed and located in accordance with the

following specifications.

Provide quick-acting Ball valve for the shower. Shower valve toremain open after the initial pull until manually closed. Locate the

face of the showerhead between 2.1 m (6.8 ft) and 2.5 m (8 ft) above

the floor.

Provide no greater than 0.6 m (23 in) horizontal distance from thecenter of the showerhead to the activating mechanism.

Provide shower unit with one activating mechanism at no higher than

1.7 m (5.75 ft) above the floor. Identify each shower location with ahighly visible sign within the area served by the shower.

Provide well-lighted area around each shower location.

Provide showerhead and pipe sizing with at least 1.26 l/sec (20 gpm)

flow, with the operating valve in the open position. Drains are not

generally provided for emergency showers. Address design and

operational issues with curbs, sloped floors, and dry drain traps for

designs incorporating drains. No obstructions, protrusions, or sharp

objects shall be located within 0.4 m (16 in) from the center of the

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