Permit To Work System

Engr. Muhammad Sajid

Lecturer

Department of Chemical Engineering, UOG

Industrial Management

SAFETY

Scope of The Session

1. Permit to work system General

Requirement

2. Isolation from hazardous materials

3. Isolation from sources of energy

4. Hot work

5. Work at height/roofs

6. Confined space entry

PTW - Participants All persons approved either to issue or

accept permits to work should have

received sufficient training and on job

experience.

This session shall be validated and recorded

by management.

This requirement also applies to contractors

staff, if working independently.

1. Permit to work system

General Requirement

Work Permit System

Hazard Identification

Obvious Hazards

Potential Hazards

Work Permit System

Takes care of Hazards from :

Electrical Source

Instruments Interlocks

Pressure

Temperature

Hazardous Materials

Others

Work Permit

When Needed

When agency doing the job does not

have operating control of the Equipment.

Types of Permits

Cold Work Permit

Hot Work Permit

Entry into confined spaces

Working on Height

Excavations/break-ins (walls/ceilings)

Electrical Isolation.

DCS Permit???

Basic Characteristics of Work Permit Clear and complete job description.

Location of the work - Area

The time span - date and time the permit comes into effect and the period of validity.

All known hazards to be listed.

List precautions to be taken to address these hazards. (Job Risk Assessment)

Electrical, process and mechanical isolation

One permit for one job for one equipment to be issued.

Communicate/reference to all other permits / authorizations.

Define PPEs

Any other precaution.

Cold & Hot Work Permits

Vessel Entry & working at Height Work Permit

Documentation

Display hard copy of the PTW at the work

site for checking

Issuer to keep the upper copy

After the completion of the job,hard copy to

be retained by the issuer& upper copy by

the receiver for audit purposes.

Work Permit Validity

Cold Work Permit:-8 Hrs(Extendable for 30 minutes by the

going shift in charge only)

Hot Work Permit:-8Hrs(Extendable for 30 minutes by the

going shift in charge only)

Vessel Entry Work Permit:-8 Hrs only, Not Extendable.

Excavation & Break-in:-8Hrs(Extendable for 30 minutes by

the going shift in charge only)

Incase after the issuance of work permit job is not

started within 2 hrs, issue the new work permit.

During emergency all work permits will be suspended.

Work Permit

Issuing Authority

Shift Engineer/Field Engineer/ Supervisor

authorized by Unit Manager.

Work Permit

Receiving Authority

Area Managers/ designated staff

of the Engineering departments.

A joint visit of the issuer and the acceptor to the site of the work is almost always

essential to discuss the hazards associated

with that job.

The signature of the issuer AND the acceptor should be recorded on the permit

Remember

The permit itself does not

make the job safe!

Joint Visit ????

Issuing Authority

Role of Issuing Authority Evaluate and discuss with the Receiving authority

the risks involved and precautions needed (Joint Visit) Joint visit is mandatory even for routine work permit jobs.

Determine Impact on other activities on the plant.

Ensure that work does not constitute an unauthorized Modification(if yes, then work after following Plant Modification & Control Procedure SP-8-00-048 & approval)

Inform to all people before work start who might get affected due to job.

Ensure that all pre-requirements of the job are fulfilled

Continued

Role of Issuing Authority

Ensure Process isolation

Ensure that procedure is complete in its entirety.

Enter the proper PPEs in work permit.

Ensure Electrical isolation (Electrical isolation must be check physically by giving start signal)

Ensure the job is proper hand over.

Job status at the end of the job completion.

Ensure that job is done within the intent of the work permit. Visit Site frequently

Extend the permit time(30 minutes), if job not completed within the shift. The new shift will issue the new permit.

Receiving Authority

Role of Receiving Authority

Together with issuer assess risks and take all precautions to make the job safe (Joint visit)

Explain to the subordinates/worker the hazards of the job and precautions to be taken.

All Engineering equipments are FIT FOR USE

Provide PPEs, as written in Work permit

Display the Work permit at work place

Stop the job if the environment/situation changed during work (ask for new work permit as per new situation/environment)

Continued

Role of Receiving Authority

Explain to persons executing the job, any specific permit requirements during the job.

Ensure that job status at the end of the day / shift / time allocated is communicated to the issuer and permit is returned to the issuer with job status & mentioned closing time on it and signed by both Receiving & Issuing authority.

Housekeeping of the area after the job.

Work Permit System

Take care of pre-requisites of Job

Isolation from Electrical Source of Energy

Isolation from Instruments Interlocks.

Isolations from Pressure Energy

Isolations from High Temperatures.

Removal of Hazardous / Toxic Materials

(Process Isolation)

Pre requisites of Job Process Isolation

Breaking Flanges

Inserting Blind Plates

Double Block and bleed

Closing / Tagging/ Chain Locks of Valves

Instruments Interlocks

Make it ineffective.

Remove Fuses

Electrical Isolation

Stop the machine first

Remove Breaker /Fuses (Rack out) and Tag the isolation Panel.

Pushing in of Emergency stop switch is not an approved method of Electrical Isolation

Process Isolation

Confirmation Through

Opening Vents.

Opening Drains

Through Pressure Indicators.

Cracking Flanges

De-contamination test through Laboratory

Work Permit System

Also takes care of POST job requirement

Area Housekeeping

Job status communication

Exchange of Work Permit copies.

Thoroughly checking of the area.

Electrical de-isolations.

Process de-isolations

Checking of smoldering after every 30 mins.(2 hours)

Hot Work Permit -

Requirement

Hot Work Any activity which generates heat, friction

or sparks(welding, cutting, grinding, heat

treatment)

Opening or working electrical equipment in

a hazardous area

Introducing equipment into a hazardous

area which is not properly certified.

ALL require an air test for flammable

atmosphere

Hot Work Permits Requirements To be accompanied by Cold Work Permit(depend).

Depressurize/ Purge / Flush equipment for removal of any combustible materials and get checked LEL % in the area.

Arrange trained Fire Watch.

Make available Fire Extinguisher of suitable type.

Ensure availability of all requisite fire fighting arrangements.

Make area wet ( If required ).

Make a tent ( If required )

Make available Fire Blanket.

Check area after the job for any smoldering debris.

Working At Height

Requirement Working At

Height 1-Area barricade. 2-Communication System & Observer.

3-Working platform as per standard provided with

Toe board

Guard rails , mid rails

Fixing of planks

Safety net(if required)

Provision of ladder for safe approach.

4-Ensure fall arresting (full body harness), mandatory at 2meter &

above.

5-Inspection of scaffolding prior to start work.(craft inspector).

Confined Space Entry Work

Permit - Requirement

Regulatory Requirement

o OSHA 29 CFR 1910.146: Permit-Required Confined Spaces - (Jan 1993)

o Identify Confined Spaces in Workplace

o Identify hazards in these spaces

o Identify procedures for controlling these hazards

o Train employees on confined space entry

o Keep records of compliance & training for all confined space activities

What is a

Confined Space?

o Large enough that an employee can enter and perform

assigned work

o Has limited or restricted means for entry or exit

o Not designed for continuous employee occupancy

o Entry - includes insertion of a persons head

Examples of Confined Spaces Vessels Reactors And tanks

Boilers

Chimneys

Holes in the ground

Drains

Manholes

pits

Principles for Safe CSE

Positive Isolation.

Clean

Ventilate

So that entry can be achieved safely

without the need for breathing apparatus

Testing the Atmosphere

The person authorized to issue entry permits

should specify in WRITING the

requirements for atmospheric testing,

covering gases to be tested for, points to be

samples and testing frequency (minimum

once every 4 hours).

Atmospheric Hazards

o Oxygen Levels - below 19.5 % or above 23.5%

o Flammable/Explosive exceeds 10% of Lower Explosive Limit (LEL)

o Toxic Substances exceed Permissible Exposure Limits (PEL)

o Beware of the use of nitrogen

Use of Tools in Confined

Spaces

Ensure tools including lights and electrical

items will be safe in the confined space

especially if flammable vapors may be

present(24 volts power supply only)

Rescue Plan

This should be prepared BEFORE entry

Communications - outside help

Specify duties of stand-by person

call for help, do NOT enter

Rescue personnel must be trained and fit

Provision of lifelines, harnesses, stretchers,

man hoists(if required),SCBA etc. to be

confirmed.

Before Approving Entry

Issuer should personally check all the

isolations

Check the certificate of air analysis &

others from Lab.

Ensure adequate standby provision.

Ensure there are back-up facilities to carry

out a rescue

Electrical Isolation Certificate

Request for de-isolation will be generated by operation department.

Switch off circuit breaker/starter of desired equipment.

Rack out / withdraw complete switchgear assembly from panel.

Detached Fuses (if available in circuit)

Earthing switch is applied in case of MV circuit only.

No voltage, confirmation from circuit breaker output and load point by

using standard VOLTMETER.

Apply the pad lock on Circuit breaker/MCC starter.

Use DO NOT OPERATE tags.

Equipment will be handed over to operation department along with signed

copy of isolation certificate

Electrical De-isolation

Removal of DO NOT OPERATE tag. Removal of pad lock from Circuit breaker/MCC starter. Disconnect Earthing switch in case of MV circuit only. Insert Fuses (if available in circuit). Rack in switchgear assembly in panel. Switch ON circuit breaker/starter of desired equipment. Voltage Supply confirmation from circuit breaker output and load point by using standard VOLTMETER

Equipment will be handed over to production department

along with signed copy of de-isolation certificate

Some Examples For

Discussion

False Information.

Area safety lock on & tag on .

All valves tagged.

Isolation, depressurization,

flushing & purging not required.

Nominated operator presence.

False Information.

Lines disconnected & blinded

Safety lock on & tag on.

Vessel is hot. Communication system

False & Missing Information

lock on & tag on.

After closing valves tagged. No information about adjacent area safe for spark.

No information about explosivity lab test.

No information about the use of copper hammer.

Status of the job. Closure time. Plant shift Engineer signature at closing.

Thanks Any Question