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Permit-Required ConfinedSpace Entry
29 CFR 1910.146
Objectives
• Understand Legislation Developed by
Government Agencies
• Identify and Use Those Regulations
• Identify a Potentially Hazardous Confined Space
Organizations• ANSI
–American National Standards Institute–Consensus Standards for Atmospheric Hazards
• NIOSH–National Institute for Occupational Safety and Health–Documents Incidents–Develops Guidelines for Safe Work
Organizations(continued)
• OSHA
–Occupational Safety and Health Administration
–Began Looking at Confined Spaces in 1975
–Cited Under General Duty Clause
–Proposed Standard Released June 1989
Permit-Required Confined Spaces29 CFR 1910.146
• Became Law April 15, 1993• Employers MUST
–Characterize the Confined Space–Provide a Permit Allowing Entry–Supply Personal Protective Equipment When
Required
• Excludes Agriculture, Construction, and Shipyards
Permit-Required Confined Spaces29 CFR 1910.146
• Large Enough and Configured Such That an Employee
Can Enter and Perform Assigned Work
• Has Limited or Restricted Means for Entry or Exit (e.g.,
Tanks, Vessels, Silos, Storage Bins, Hoppers, Vaults, and Pits)
• Is Not Designated for Continuous Employee Occupancy
A Confined Space is...
Permit-Required Confined Spaces29 CFR 1910.146
• Contains or Has Potential to Contain a Hazardous Atmosphere
• Contains a Material That Has the Potential for Engulfment
• Internal Configuration of Inwardly Converging Walls or Sloping
and Tapering Floor
• Contains Any Other Recognized Serious Safety or Health Hazard
A Permit-Required Confined Space...
Permit-Required Confined Spaces29 CFR 1910.146
• Surrounding and Capture of a Person• Liquid or Finely Divided (Flowable) Solid• Can Cause Filling or Plugging of Respiratory
System Via Aspiration• Can Exert Enough Force on Body to Cause Death
by Strangulation, Constriction, or Crushing
Engulfment...
Permit-Required Confined Spaces29 CFR 1910.146
• Immediate or Delayed Threat to Life• Causes Irreversible Adverse Health Effects• Interferes With the Ability to Escape from a
Permit Space
Immediately Dangerous to Life or Health (IDLH)...
Permit-Required Confined Spaces29 CFR 1910.146
• Flammable Gas, Vapor, or Mist >10% of LFL (LEL)
• Airborne Combustible Dust > LFLDust Obscures Vision at a Distance of 5 ft. or less
• Oxygen < 19.5 % or > 23.5%• Exposures in Excess of OSHA’s PELs
IDLH Conditions...
Employer’s Responsibilities
• Determines Whether Permit-Required Confined Spaces Exist(Appendix A - Flow Chart)
• Informs Employees and Posts Warning Signs• Prevents Entry If Employees are Not to Work in
PRCS
Employer’s Responsibilities(continued)
• Develop and Implement a Written Permit Entry Program
• May Use Alternate Procedures• If a Non-Permit Space is Reconfigured, Re-
evaluation of the Space is Required• Must Inform Contractors and Use Permitting
Program
DANGER
CONFINED SPACE
ENTER BY PERMIT ONLY!
Permit-Required Confined SpaceELEMENTS OF THE PROGRAM
• Prevent Unauthorized Entry• Identify and Evaluate the Hazards Prior to Entry
(Appendix B- Who Can Do This, & How)
• Develop Safe Entry Procedures– Acceptable Entry Conditions– Isolating the Permit Space– Purging, Inerting, Flushing, or Ventilating– Barriers to Protect from External Hazards
Permit-Required Confined Space(PRCS)
• Testing and Monitoring Equipment
• Ventilating Equipment
• Communications Equipment
• Personal Protective Equipment
Equipment
Permit-Required Confined Space(PRCS)
• Lighting
• Barriers and Shields
• Ladders and Other Entry/Egress Equipment
• Rescue and Emergency Equipment
Equipment (continued)
Permit-Required Confined SpaceELEMENTS OF THE PROGRAM
(continued)• Evaluate Space Before and During Work• Provide at Least One Attendant Outside for the
Duration of Entry Operations• Multiple Space Response Procedures• Designate Active Roles• Rescue and Emergency Response Procedures
Permit-Required Confined SpaceELEMENTS OF THE PROGRAM
(continued)• System for Preparation, Issuance, Use and
Cancellation of Permits• Procedures for Multiple Employer Worksites• Procedures for Closing Space• Review of Entry Operations• Review of Program
Permit-Required Confined Space(PRCS)
• Permit System• Entry Permit• Training• Other Appendices
–Appendix C: Example Situations–Appendix D: Example Check List & Permit–Appendix E: Sewer System Entry
Permit-Required Confined SpaceThe Permit
1. DATE:____ TIME:____ A.M../P.M. 2. VESSEL # 3. JOB # 4. LOCATION:
5.DESCRIPTION OF WORK:
6.PHYSICAL HAZARD ASSESSMENT: Engulfment, Electrical, Steam, Augers, Chain Drives etc..
7. CORRECTIVE MEASURES: Physical Disconnects, Lockout / Tagout etc..
8. ATMOSPHERIC ASSESSMENT: Oxygen, LEL, CO, H2S (Other)
9. Instrument # 10. Calibration Date: 11. Name of Operator:
12. Substance 13. P.E.L. 14. Actual
15. Oxygen 16. < 19.5% or > 23.5% 17. Other
18. LEL > 10% 20.
21. Carbon Monoxide (CO) 22. 50 ppm 23. Other
24. Hydrogen Sulphide (H2S) 25. 10 ppm 26. Other
27. PPE 28. Respirators 29.Rescue Equipment
30. Other 31. Other 32. Other
33. Names of entrants, Attendants, and Entry Supervisors:
34. Time work / shift completed: (35.) Problems / concerns
36. Emergency contact:
Other OSHA Regulations
Hazard Communication
–29 CFR 1926.59–MSDS–Training–Labeling–Written Program
Control of Hazardous Energy Sources–29 CFR 1926.417 & 1910.147
–“Lock Out/Tag Out”
–De-Energize ALL Sources of Energy
–Written Program
Permit-Required Confined Spaces
Administrative Controls
Permit Space Entry Program
Learning Objectives
• Describe the Guidelines for a Permit-Required Confined Space Program
• Identify Conditions Which Allow the Use of Alternate Procedures
General Requirements
• A Written Permit Space Program• Authorized Personnel• Confined Space Evaluation Procedures• Acceptable Entry Conditions and Procedures
PRCS ProgramThe Entry Permit Shall Identify:
1) The Permit Space to be Entered.2) The Purpose of the Entry.3) The Date and Duration.4) The Authorized Entrants.5) The Attendants.6) The Entry Supervisor.7) The Hazards of the Space to be Entered.8) Measures to Isolate and Eliminate the Hazards Before Entry.
9) The Acceptable Entry Conditions.
10) The results of Initial and Periodic Tests with Initials of
Testers.
PRCS ProgramThe Entry Permit Shall Identify:
11) The Rescue and Emergency Services That Can Be
Summoned.
12) The Communication Procedures Used By Entrants and
Attendants.
13) Equipment such as Testing, Communication and
Emergency Equipment.
14) Any Other Information Necessary, In Order To Ensure
Employee Safety.
15) Any Additional Permits Such As a Hot Work Permit.
Authorized Entrant Duties
• Knows Hazards, Symptoms, and Consequences
• Proper Use of Equipment
• Communicate With Attendant
• Exit Promptly From PRCS When Necessary
Attendant Duties• Knows Hazards, Symptoms, and Consequences
• Awareness of Behavioral Effects of Exposure
• Continuously Identifies Number and Identity of Entrants
• Remains Outside of PRCS
• Communicates With Entrants
Attendant Duties
• Monitors Entrant & Surrounding Activity• Summons Rescue If Needed• Keeps Unauthorized Persons Away From PRCS• Performs Non-Entry Rescues• Performs Only Attendant Duties
Entry Supervisor Duties
• Knows Hazards, Symptoms, and Consequences
• Verifies Performance of Permit Testing, Procedures and Equipment
• Terminates PRCS Entry and Permit
Entry Supervisor Duties
• Verifies Availability and Communication With Rescue Services
• Removes Unauthorized Personnel• Determines Compliance With the Entry
Permit
Rescue and Emergency Services
• Trained in PPE and Rescue Equipment• Trained in Rescue and Authorized Entrant Duties• Practice Rescues Once Every 12 Months
– Simulated With Mannequins or People– In Actual PRCS
• Trained in CPR and Basic First Aid–At Least 1 Member of Rescue Service Holding Current
Certification
Using Employer’s Personnel...
Rescue and Emergency Services
• Must Be Informed of Hazards Prior to Arrival
• Must Have Access to All Spaces to Assess and Allow for Practice of Rescues
Outside Rescue Service...
Rescue and Emergency Services
“Retrieval Systems or Methods Shall Be Used Whenever an Authorized Entrant Enters a PRCS”– Unless Equipment Increases Risk or Would Not Assist Rescue
– Chest or Full Body Harness, Center of Back Near Shoulder or Above
Head; Wristlets ONLY if Harness is Infeasible or Greater Hazard
– Attached to Mechanical Device or Fixed Point Outside Space
– MSDS Must Be at Worksite and Furnished to Medical Facility Treating
Exposed Entrants
Non-Entry Rescue...
Testing and MonitoringAppendix B
• Evaluation Testing–Any Hazards–Prior to Entry– Technically Qualified Professional
• OSHA Consultation Service• CIH• Registered Safety Engineer• CSP
• Verification Testing
Testing and MonitoringAppendix B
• Duration of Testing
• Testing Stratified Atmospheres–Atmospheric Envelope of 4 ft. in Direction of Travel
and to All Sides–Rate of Progress of Entrant Slowed to Accommodate
Instrument Sampling Speed and Response Time
Hot Work PermitsDefined As: Written Authorization to Perform
Operations Capable of Providing a Source of Ignition (Such As Welding, Cutting, or Brazing)
Required for: Hot Work in Grain Handling Facilities and Any Other Combustible/ Explosive Areas
Hot Work PermitsGeneral Provisions
• Remove Fire Hazards & Combustibles• Guard the Work• Guard Openings to Other Areas• Maintain Fire Extinguishers
Hot Work PermitsGeneral Provisions
• Maintain Fire Watch• Written Permit Authorization• Protect Floors & Walls• Protect Drains, Dusts, and Pipes
Alternate Procedures
• ONLY Hazard is an Actual or Potential Hazardous Atmosphere
And• Can Demonstrate That Continuous Forced Air is
Sufficient to Maintain the Space as Safe• Data is Developed to Support the Above• A Permit Program is Followed During Data
Collection
Can be used if...
Alternate Procedures(continued)
• Hazard from Removing Entrance Cover is Eliminated
• Entrance is Made Safe to Prevent Accidental Falls• Atmospheric Testing for
– Oxygen– Flammability– Toxic Contaminants
Alternate Procedures(continued)
• No Hazardous Atmospheres Develop While Employee is In Space
• Continuous Forced Air Ventilation is Used–No Entry Until Safe–Remains Until Everyone Has Left Space–Air is From a Clean, Safe Source
• Periodic Testing
Alternate Procedures(continued)
• If A Hazard Develops–Evacuation of Space–Evaluation as to the Source–Protection of Employees Prior to Re-entry
• Documentation–Date, Location, Signature of Person Certifying–Certification Made Prior to Entry and Available to
each Employee
• If the Stated Conditions Are Met, the Employer Does Not Have to Implement
• OSHA Compliance Letter (10/12/95) Interprets the Elimination Provision: “… If the Non-Atmospheric Hazards Were Permanently Eliminated, the Alternate Procedures Could Subsequently Be Applied…”
Alternate Procedures(continued)
At Issue -“Elimination” of Hazards
–PRCS Program–Permit System–Entry Permit
–Personnel Duties–Rescue–Emergency Services
Hazards are usually dictated by...
• The material stored in the confined space.
• The activity carried out in the confined space. (a particular chemical reaction)
• The external environment. (a tank located near rising waters)
OSHA Estimates• 224,000 establishments have permit required
confined space.
• 2.1 million workers enter these spaces annually.
• 60% of the deaths that occur in confined spaces are the rescuers who go in after the victim.
Confined Space Hazards• Chemical Hazards
• Physical Hazards
• Biological Hazards
• Ergonomic Hazards
Engulfment
• The surrounding or covering of a person by a liquid or flowable solid. Death may result by suffocation, strangulation, constriction, or crushing.– Concrete– Asphalt
Primary Constituents of Normal Air(Permanent Gases)
ConstituentChemicalFormula
MolecularWeight
Percentby Volume
Nitrogen
Oxygen
Argon
N2
O2
Ar
28
32
40
78.1
20.9
0.9
Water vapor content varies, but is usually the third largest constituent by volume in air.
Definitions of O2 Deficient Atmosphere
Source Oxygen Content
29 CFR 1910.146 (PRCS) <19.5%
42 CFR Part 84 (NIOSH Resp. Approval) <19.5%
29 CFR 1910.134(g) (Resp. Std.) 16.0%1
29 CFR 1910.94 (Ventilation. Std.) <19.5%
29 CFR 1915.11(b) (Shipyards) <19.5%
ANSI Z117.1-1995 (Confined Spaces) <19.5%
ANSI Z88.2-1992 (Respirator Practices) 16.0%2
ACGIH (TLV booklet) 18.0%
1 Letter of interpretation
2 Oxygen partial pressure <122 mmHg. Confined space with <20.9 % O2 is IDLH, unless source of O2 reduction is understood and controlled.
Oxygen-Deficient AtmospheresO2 Content
15-19%
Effects and Symptoms (at patm)
Decreased ability to work strenuously. May impair coordination and induce early symptoms in persons with coronory, pulmonary, or circulatory problems.
Respiration increases in exertion, pulse up, impaired coordination, perception, and judgment.
Respiration further increases in rate and depth, poor judgment, lips blue.
Mental failure, fainting, unconsciousness, ashen face, blueness of lips, nausea, and vomiting.
8 min., 100% fatal; 6 min., 50% fatal; 4-5 min., recovery with treatment.
Coma in 40 sec., convulsions, respiration ceases, death.
12-14%
10-12%
8-10%
6-8%
4-6%
NOTE: Exposure to atmospheres containing 12% or less oxygen will bring about unconsciousness without warning and so quickly that individuals cannot help or protect themselves.
How an Oxygen-Deficient Atmosphere Can Occur in a Confined Space
1. Consumption 3. Adsorption
a) a)
b)
c)
2. Displacement
a)
b)
c)
Argon (Ar)
• Colorless, odorless inert gas• Slightly lighter than air
• Colorless, odorless inert gas• Heavier than air
Nitrogen (N2)
Argon (Ar)
• Colorless, odorless inert gas• Heavier than air
Methane (CH4)
• Natural, marsh, swamp gas• Colorless, odorless flammable gas• Lighter than air• Toxic?• LEL = 5%; UEL = 15%
Carbon Dioxide (CO2)• Colorless, odorless noncombustible gas• Heavier than air• Common in solid and compressed liquid forms• Carbonation• Inerting• Organic decay (grain elevators, sewers, storage bins,
wells)• Fermentation (digestors, molasses pits, beer and wine
vats)
CO2 (cont’d)
• PEL = 5,000 ppm - TWA (Table Z-1)• TLV/REL = 5,000 ppm - TWA; 30,000 ppm - STEL• IDLH = 50,000 ppm• LEL = none
Carbon Monoxide (CO)
• Colorless, odorless gas• Slightly lighter than air• Chemical asphyxiant• Primary source: incomplete combustion of
organic material• Gasoline-fueled combustion engines
CO (cont’d)
• PEL = 50 ppm - TWA• TLV = 25 ppm - TWA• BEI: <3.5% COHb; 20 ppm (end-exhaled air)• REL = 200 ppm - STEL; 35 ppm - TWA• IDLH = 1500 ppm• LEL = 12.5%; UEL = 74.2%
Concentration of CONecessary to Produce Symptoms
Percent ppm Effects
0.02 200 Possibly headache, mild frontal in 2-3 hrs.
0.04 400 Headache, frontal, and nausea after 1-2 hrs.; occipital after 2-1/2 to 3-1/2 hrs.
0.08 800 Headache, dizziness and nausea in 3/4 hour, collapse and possible unconsciousness in 2 hrs.
0.16 1,600 Headache, dizziness and nausea in 20 min.; collapse, unconsciousness, possibly death in 2 hr.
0.32 3,200 Headache and dizziness in 5 to 10 min., unconsciousness and danger of death in 30 min.
0.64 6,400 Headache and dizziness in 1 to2 min., unconsciousness and danger of death in 10 to 15 min.
1.28 12,800 Immediate effect; unconsciousness and danger of death in 1 to 3 min.
(Source: Hamilton & Hardy)
Symptoms of CO Exposure
Percent* Symptoms
0-10 Shortness of breath on exertion
10-20 Tightness across forehead, slight headache
20-30 Throbbing headache
30-40 Severe headache, nausea, vomiting, collapse on exertion
40-50 All symptoms increased, pulse rate and breathing increased
50-70 Coma, interrupted breathing (Cheyne-Stokes), death
* Percent saturation of Hemoglobin with CO [Blood Levels]
Hydrogen Sulfide (H2S)• Sewer gas, stink gas (rotten eggs)• Odor threshold: 0.02 - 0.2 ppm• Colorless, flammable gas• Heavier than air• PEL = 20 ppm - C; 50 ppm - Peak (10 min. once)• TLV = 15 ppm - STEL; 10 ppm - TWA• REL = 10 ppm - C (10 min.)• IDLH = 300 ppm• LEL = 4.3%; UEL = 46%
H2S (cont’d)
• PEL = 20 ppm - C; 50 ppm - Peak (10 min. once)• TLV = 15 ppm - STEL; 10 ppm - TWA• REL = 10 ppm - C (10 min.)• IDLH = 300 ppm• LEL = 4.3%; UEL = 46%
Effects of H2S Concentrationppm* Local Systemic
20
50 Irritant of conjunctival and
corneal epithelium
50-100 Eye and respiratory tract
irritation in 1 hr.
100-150 Slight systemic symptoms after several hrs.
150 Olfactory nerve paralysis Fatal in 8-48 hrs.
200 Pulmonary irritation and pulmonary Nervous system depression
edema after prolonged exposure
* Concentration by Volume
Effects of H2S Concentration (cont’d)
ppm* Local Systemic
250-350 Fatal in 4-8 hrs.
350-450 Fatal in 1-4 hrs.
500-600 Excitement, headache, dizziness and unconsciousness, death in 30-60 min.
600-700 Rapid collapse, death in 2-15 min.
700-2,000 Cessation of respiration, rapidly fatal
* Concentration by Volume
May arise from the:1. Product(s) stored
2. Manufacturing processes
3. Work being performed
4. Adjacent areas
Other Toxics
Definitions• Vapor Pressure- Pressure exerted by a vapor. If a
vapor is kept in confinement over its liquid so that the vapor can accumulate above the liquid, the vapor pressure approaches a fixed limit called the maximum vapor pressure. (How much the liquid wants to become a gas)
• Flash Point- The minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid.
Flammable/Combustible Liquid Classification(29 CFR 1910.106)
IIIB (NFPA)
IIIA
II
IC
IB
IA
BOILING POINT
Flammable is <100F0
Combustible is >100F0
100F0
Flammable (Explosive) Limits• When vapors of a flammable or combustible liquid are mixed with air in the
proper proportions in the presence of a source of ignition, rapid combustion or an explosion can occur. The proper proportion is called the flammable range and is also often referred to as the explosive range. The flammable range includes all concentrations of flammable vapor or gas in air, in which a flash will occur or a flame will travel if the mixture is ignited. There is a minimum concentration of vapor or gas in air below which propagation of flame does not occur on contact with a source of ignition. There is also a maximum proportion of vapor in air above which propagation of flame does not occur. These boundary-line mixtures of vapor with air are known as the lower and upper flammable or explosive limits (LFL or UFL) respectively, and they are usually expressed in terms of percentage by volume of vapor in air.
Atmospheric Pressure
• Atmospheric pressure is 760 mmHg a substance with a vapor pressure of 760 mmHg is a gas at room temperature.– Water vapor pressure= 25 mmHg– Fuel oil vapor pressure= 2 mmHg– Vinyl chloride vapor pressure= (760 mmHg)(3.4)
• “1300 rule”– 1300*VP= concentration just above the surface of the
liquid
MSDS Exercise
• What color is this substance?• What type of odor does it have?• What PEL or TLV is set for this substance?• What are some of the synonyms for this substance?• What products are incompatible with this product?• What type of PPE should be worn while handling this product?• What are some of the symptoms of overexposure?• If a co-worker was overexposed to this product what information should be
give to medical personnel?• Is this substance designated as a hazardous waste by the EPA?• Who might you call for more information about this product?
Air Monitoring
Permit-Required Confined Spaces
Objectives
• Describe Why the Work Environment Needs to Be Monitored
• Understand the Value of Personal, Area, and Perimeter Monitoring
• Identify Several Types of Monitoring Equipment
Why Do Monitoring?
• To Detect if Potential Hazardous Conditions
Exist
• To Measure Concentrations of Hazardous
Substances
Detection of Hazards• To Determine Whether Hazardous Materials Are
Present Under Normal Conditions• Whether the Environment is IDLH• Measure Releases During Work to Ensure Proper
PPE and Work Practices• Ensure That No Hazardous Materials Remain
After a Release
Hazards In The Air
• Oxygen Deficiency/Enrichment• Explosive Atmospheres• Toxic Chemicals• Radioactivity• Biological Hazards
Oxygen
Oxygen Deficient
Oxygen Enriched23.5%
19.5%
16.0%
14.0%
6.0%
Minimum for Safe Entry
Impaired Judgment& Breathing
Faulty JudgmentRapid Fatigue
Difficulty in BreathingDeath in Minutes
Explosive Limits
Combustible
UEL
LEL
Too Lean
Too Rich
10% of LEL
Personal Air Monitoring
• Accurate Measure of Actual Exposure
• Compares to OSHA PEL, STEL
• Documents Exposure• Allows Appropriate
PPE Selection
• Lab Analysis 1 to 14 Days
• No Peak or Ceiling Measures
• Need to Know What Exposures are Possible
• Preparation and Calibration Needed Prior and Following
PRO CON
Personal Monitoring Equipment
• Battery Operated Sampling Pumps–Filters - Fumes/Particles/Mists–Charcoal Tubes - Gases/Vapors–Silica Gel Tubes - Gases/Vapors
• Passive Badge DosimetersGases and Vapors
Real-Time Measurements
• Immediate Measures• Measures Variety of
Exposures• Measures IDLH
Situations• Detects Peak Toxic
and Flammable Levels• Determines Ability to
Enter PRCS
• May Not Detect “Low” Levels
• Not Specific• May False Alarm• Interferences and
Cross Sensitivity• May Require Factory
Calibration
PRO CON
Direct Reading Instruments
• Oxygen Meter• Explosive Gas Meter/Combustible Gas Indicator• Detector Tubes• Personal Alarm Monitors• Multi-Gas Analyzer/Meters
Examples of Direct Reading Instruments
Review
• Where Are Measurements Taken?• What Types of Measurements Can Be Made?• How Are These Measurements Used?• What Are Some of the Limitations of Air
Sampling?
Instrumentation
• O2 Meters– Use O2 Meters
• Flammable Gases and Vapors– Use Combustible Gas Indicator
• Toxic Air Contaminants– Use Colorimeteric Detector Tubes
Combustible Gas Indicators
• Used to sample vapor concentrations near and in permit spaces
• Reads LEL
• A reading above 10% should be considered a potentially explosive atmosphere
Combustible Gas IndicatorsPrecautions
• The equipment may not respond the same to all vapors
• O2 MUST BE MEASURED FIRST!
Oxygen Meters• Used to sample oxygen concentrations in and near
confined spaces.• Reads between 0-25% or 0-100%• At greater than 23.5% O2, the explosion hazard
increases.• At less than 19.5% the space cannot be entered
without a SCBA or SAR with escape pack.
Oxygen Meter Precautions
• Very sensitive to temperature and pressure changes.
• At high concentrations of carbon monoxide, the meter may give improper readings.
• Must be calibrated before every use!
Colorimeteric Detector Tubes
• Used to sample gas or vapor concentration in any work space.
• Reads percent of the concentration in PPM.
• Concentration indicated by color change or length of color stain.
Detector Tube Precautions
• They are not very accurate-- within 25% of the real value at best.
• The tubes are very sensitive to temperature and humidity.
• Different tubes must be used for different chemicals.
• They are breakable.
Tips To Help In Monitoring
• Check the accuracy of the instruments you are going to use.– Have they been recently calibrated?
• Always test in this order: Oxygen, Flammability/Combustibility, and Toxic Gases.
• Test the air from the top to bottom including all corners and spaces!
• Test the atmosphere frequently!
Ventilation of Permit-RequiredConfined Spaces
Comfort - General/Dilution Ventilation
• Temperature and humidity regulationsASHRAE 55-1992– Winter: 68 - 74oF– Summer: 73 - 79oF– RH: 30 - 60 %
Comfort - General/Dilution Ventilation (cont’d)
• Odor removal - outside air movementASHRAE 62 - 1989– Public bathrooms: 50 CFM/wc or 2 CFM/ft2
– Office: 15 CFM/person– Smoking lounges: 20 - 60 CFM/person
Safety - General/Dilution Ventilation
Fire and explosion control
LELVV = cubic feet of vapor per gallon of solvent (vapor volume)
Dilution volume =4(100-LEL)VV
(1) Volume of air required to dilute the vapor from 1 gallon of solvent to 25% LEL. [1910.94(c)(6)(ii)]
Safety - General/Dilution Ventilation (cont’d)
Example: acetone
2.5
= 6,864 ft3 air / gal acetone (70oF)
Dilution volume =4(100-2.5)44.0
Safety - General/Dilution Ventilation (cont’d)
LELDilution volume =
10(100 - LEL)VV
(2) Volume of air required to dilute the vapor from 1 gallon of solvent to 10% LEL. [1910.146(b)]
Safety - General/Dilution Ventilation (cont’d)
Example: acetone
2.5Dilution volume =
10(100 - 2.5)44.0
= 17,160 ft3 air / gal acetone (70oF)
Ventilation Volume Calculation
Ventilation volume = Dilution volume x Gallons of solvent evaporated per minute
CFM = ft3 air
gal solvent
gal solvent
minx
Ventilation Volume Calculation (cont’d)
Example: Acetone-thinned paint applied at rate of one gallon per minute. Paint is 40% solvent.
Ventilation volume (for 25% LEL)
6,864 ft3 air 1 gal paint 0.4 gal solvent
gal solvent min gal paint
x x = 2,746 CFM
Ventilation volume (for 10% LEL)
17,160 ft3 air 1 gal paint 0.4 gal solvent
gal solvent min gal paint
x x = 6,864 CFM
Dilution Ventilationfor Fire and Explosion
• Reduce the concentration of vapors within an enclosure to below the LEL.
• This concept is never applied in cases where workers are exposed to the vapor. Dilution rates for health hazard control are always applied in these instances, since the PEL is a much lower concentration than the LEL.
Safety - Dilution Ventilation
403(SG)(100)(C)(w)
(MW)(LEL)(B)Q =
where,
Q = air flow rate (CFM) required to dilute vapor concentration to safe condition
403 = conversion factor
SG = specific gravity of liquid (water = 1)
Safety - Dilution Ventilation (cont’d)
100 = constant to convert LEL to decimal fraction
C = dimensionless safety factor which depends on % LEL necessary for safe conditions (10% LEL: C = 10, 25% LEL: C = 4)
w = pints of liquid evaporated in one minute
MW = molecular weight of vapor
LEL = lower explosive limit (%)
B = constant reflecting fact that LEL decreases at elevated temperatures (£ 250oF: B = 1, > 250oF: B = 0.7)
Flammable Liquid Storage Rooms
Ventilation must provide for a complete change of air within the room at least six times per hour (6 A.C. / hr).
Exchanging all the air in the room is equivalent to 1 A.C. [i.e., Room volume (L x W x H) = 1 A.C.]
6 A.C. / hr = (6 x Room volume) / hr
CFM = [6 x Room volume (ft3)] x 1 hr / 60 min
CFM = Room volume (ft3) / 10
Health - Dilution Ventilation
403(SG)(106)(w)(K)
(MW)(PEL)Q =
where,
Q = air flow rate (CFM) required to dilute vapor concentration to the PEL.
K = dimensionless safety factor (varies from 3-10) to maintain concentration well below PEL. Higher value for high toxicity, high evolution rate, poor ventilation, and large number of exposed workers.
Considerations for PRCS Ventilation
• Space configuration• Ventilation mode (exhaust/supply)• Ventilation flow rate• Availability of make-up air• Obstacles for ducting• Availability of power sources• Location of employee within space• Characteristics of contaminant
Achievement of Accceptable Atmospheres
• Dilution - use general/forced air ventilation to dilute the contaminant
• Exhaust - use local exhaust ventilation to remove the contaminant
• Dilution/Exhaust - use a combination of both methods to remove the contaminant
Dilution Ventilation
• Introduces fresh air to space• Best when toxicity levels
and concentrations are low• Best when contaminants
well distributed• Requires larger air volume
when contaminants generatedat a point
Local (Source) Ventilation
• Exhausts from a localized area• Removes high concentrations
of contaminants from space• Requires smaller volume
of air
Solutions
• Inerting• Purging• Ventilation
Inerting
• Displacement of the atmosphere by a non-reactive gas (such as nitrogen) to such an extent that the resulting atmosphere is noncumbustible.
Purging• The method by which gases, vapors, or other airborne
impurities are displaced from a confined space.• Purpose is to do a complete air exchange in a confined space
prior to entry. Normally, a purge is considered complete when atmospheric tests indicate the air is of suitable quality to sustain life.
Inerting• Displacement of the atmosphere by a non-reactive gas
(such as nitrogen) to such an extent that the resulting
atmosphere is noncumbustible.
Ventilation
• At opening of blower 100% capacity
• Blower plus 25’ of hose 78% capacity
• 25’ of hose plus one 90 degree bend 67% capacity
• 25’ of hose plus two 90 degree bend 56% capacity
Electricity
• Electricity Doesn’t Spring Into Action Until Current Flows
• Current Doesn’t Flow Until there is a Loop to and from the Transformer
• Current Always Returns to the Transformer that created it
Electricity
• Voltage Water Pressure• Ohms Resistance / Size of Water Pipe• Current Flow Rate of Water
Electrical Shock
• Contact with a normally energized conductor (wire).
• Contact with an energized conductor on which the insulation has lost it’s protective value
• Equipment failure, causing an open or short circuit• Static Electricity Discharge• Lightning Strike
Cords & Corded Equipment• Do not remove ground plug• Flexible cords must Not be:
Used instead of fixed wiringRun through holes in ceilings, walls, or floorsRun through doorways, windows, or openingsConcealed in walls, ceilings, or floors
• Flexible cords may be used for:PendantsFixture wiringPortable lamps or appliancesCranes and hoistsFrequently Moved equipment
Lockout/Tagout
29 CFR 1910.147Control of Hazardous Energy Sources
(Lockout/Tagout)
Scope 1910.147 (a)(1)(i)
• Covers servicing and maintenance of machines when unexpected startup or release of stored energy could cause injury.
Application 1910.147 (a)(2)(i)
• Standard applies to control of energy during servicing and/or maintenance.
• Note: Servicing / maintenance during normal production operations is covered if:
an employee is required to remove or bypass a guard, or
an employee must place his / her body into danger zone
Does not cover: 1910.147 (a)(1)(ii)
• Construction, agriculture, maritime• Installations under control of electric utilities• Exposure to electrical hazards from work on,
near, or with conductors or equipment in electrical utilization installations (see Subpart S)
• Oil and gas drilling, and servicing
Also Excluded 1910.147 (a)(2)(ii) & (iii)
• Normal production operations (see Subpart O)• Work on cord and plug connected equipment• Hot tap operations, under special conditions
Definitions 1910.147 (b) & (c)(7)(i)(C)
*While not defined in 1910.147 (b), “other employees” are discussed in 1910.147 (c)(7)(i)(C).• Authorized Employee: Person who locks or tags machines / equipment to perform servicing.
• Affected Employee: One who is required to use machines / equipment on which servicing is performed under lockout / tagout or who must work in such an area.
• Other Employees: * All employees whose work operations are or may be in an area where energy control procedures may be utilized.
Definitions (continued) 1910.147 (b)
“Capable of being locked out”• Designed with hasp or attachment to which lock
can be affixed; or,• Has locking mechanism built in; or, • Lockout can be achieved without need to
dismantle, rebuild, replace or permanently alter.
Definitions (continued)1910.147 (b)
• Normal Production Operations: Utilization of a machine or equipment to perform its intended function.
• Servicing and/or Maintenance: Includes lubrication, cleaning or unjamming, making adjustments and tool changes, where employees may be exposed to UNEXPECTED energization, startup or release of hazardous energy.
Energy Control Program1910.147 (c)(1)
• The employer shall establish a program consisting of an energy control procedure and employee training... in accordance with paragraph (c)(4) of this section.
Lockout vs. Tagout
• Lockout system is preferred method and shall be used when equipment can be locked out -- unless employer can show that tagout system provides full employee protection.
Full Employee Protection1910.147 (c)(3)(i)
• When tagout is used on equipment which is capable of being locked out:
Tags shall be attached where lockout devices would be; and,
Employer must demonstrate that tagout will provide safety equivalent to lockout.
Energy Control Procedure1910.147 (c)(4)(i)
• Procedures shall be developed, documented and utilized for the control of potentially hazardous energy when employees are engaged in servicing and maintenance.
Energy Control Procedures must be written, unless all of the following exist: 1910.147 (c)(4)(i) -
exception• Equipment has no potential for stored / residual energy.• Equipment has a single energy source.• Isolation and lockout of one energy source completely
deactivates equipment.• Equipment is isolated from energy source & locked out.• Lockout device is under exclusive control of authorized
employee performing maintenance.• No other hazards are created.• Employer has had no related accidents.
Procedures must contain: 1910.147 (c)(4)(ii)• Scope
• Purpose• Authorization• Rules• Techniques to be utilized• Means to enforce compliance
Materials / Hardware1910.147 (c)(5)
• Provided by employer• Singularly identified• Only devices used• Not used for other purposes• Durable• Standardized• Substantial
Periodic Inspection 1910.147 (c)(6)(i)• At least annually
• Performed by authorized employee (other than the one(s) using procedure being inspected).
• Designed to correct deficiencies.• Lockout: Must review each authorized employee’s
responsibilities.• Tagout: Must review each authorized and affected employee’s
responsibilities and additional training requirements of 1910.147 (c)(7)(ii).
• Employer certification required.
Training1910.147 (c)(7)(i)
• Authorized Employee– Recognition of hazardous energy sources– Type & magnitude of energy in workplace– Methods for energy isolation / control
• Affected Employee– Purpose / use of energy control procedure
• Other Employee– Procedure– Prohibition on restarting machines or equipment
Additional Training - Tagout System 1910.147 (c)(7)(ii)
• Employees shall be trained in the limitations of tags, as follows:– Warning devices only– Must not be removed / bypassed / ignored– Must be legible– Must withstand environmental conditions– May (will) evoke false sense of security– Must be securely attached
Employee Retraining 1910.147 (c)(7)(iii)
• Provided when:–Change in job assignments–Change in machines, equipment or processes
that present new hazards–Change in energy control procedures–Periodic inspection reveals, or employer has
reason to believe, there are deviations in employee knowledge of procedures
Specific Procedures 1910.147 (d)(1) - (6)
• Lockout / Tagout procedures shall cover the following elements in the following sequence:–Preparation for shutdown–Shutdown – Isolation–Lockout / tagout device application–Release of stored energy–Verification of isolation
Release from Lockout / Tagout 1910.147 (e)(1) - (3)
• Prior to restoring energy, the following procedures are required:–Inspect machine and equipment–Safe positioning and notification of
employees–Removal of lockout / tagout device
Testing of Machines 1910.147 (f)(1)
• When lockout / tagout devices must temporarily be removed for testing / positioning:–Clear machine of tools / equipment–Remove employees–Remove lockout / tagout device–Energize and test–De-energize and reapply energy control measures
Outside Personnel (Contractors) 1910.147(f)(2)
• On-site employer and outside employer shall inform each other of their respective procedures.
• On-site employer shall ensure that his / her employees understand and comply with contractor’s procedures.
Group Lockout / Tagout1910.147 (f)(3)
• Additional Requirements–Primary responsibility is vested in an authorized
employee for a set number of employees.–Authorized employee must ascertain exposure status of
group members.– If more than one crew is involved, coordinator needed.–Each authorized employee shall use a personal
lockout / tagout device and remove it when finished.
Shift / Personnel Changes 1910.147 (f)(4)
• Specific procedures needed to ensure continuity of lockout / tagout protection.
Lockout/TagoutPurpose - 1910.147(a)(3)
This section requires employers to establish a program andutilize procedures for affixing appropriate lockout devices ortagout devices to energy isolating devices, and to otherwisedisable machines or equipment to prevent unexpected energization, start-up or release of stored energy in order toprevent injury to employees.
Lockout/TagoutDefinitions - 1910.147(b)
Affected employee: An employee whose job requires him/her to operate or use a machine or equipment on which servicing or maintenance is being performed under lockout or tagout, or whose job requires him/her to work in an area in which such servicing or maintenance is being performed.
Authorized employee: A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment. An affected employee becomes an authorized employee when that employee’s duties include performing servicing or maintenance covered under this section.
Energy isolating device: A mechanical device that physically prevents
the transmission or release of energy.
Lockout/TagoutEmployer Responsibilities
Education– Documentation: a written statement of company’s Energy
Control Plan.– Employee training: to help employees in the use of the Energy
Control Plan.
Enforcement– Inspection: to make sure energy control procedures are being
carried out.– Self-audit: a periodic review of the procedures and the
program.
Lockout/TagoutGeneral - 1910.147(c)
The employer shall establish a program consisting of energycontrol procedures, employee training and periodic inspectionsto ensure that before any employee performs any servicing ormaintenance on a machine or equipment where the unexpectedenergizing, start up or release of stored energy could occur andcause injury, the machine or equipment shall be isolated fromthe energy source, and rendered inoperative.
Lockout/TagoutApplying Energy Controls
• Energy isolation and lockout/tagout are to be applied only by trained employees authorized to perform service or maintenance.
• Before lockout/tagout is applied, all employees who work in the affected area must be notified.
• The OSHA regulation requires that control of hazardous energy be done according to a six-step procedure.
Lockout/TagoutPreparation for Shutdown - 1910.147(d)(1)
• The types and amounts of energy that power it• The hazards of that energy• How the energy can be controlled
Before you turn off any equipment in orderto lock or tag it out, you must know:
Lockout/TagoutEquipment Shutdown - 1910.147(d)(2)
• Shut the system down by using its operating controls.
• Follow whatever procedure is right for the equipment, so that you don’t endanger anyone during shutdown.
• An orderly shutdown must be utilized to avoid any additional or increased hazard(s) to employees as a result of the equipment stoppage.
Lockout/TagoutEquipment Isolation - 1910.147(d)(3)
• Operate all energy-isolating devices so that the equipment is isolated from its energy sources.
• Be sure to isolate all energy sources-secondary power supplies as well as the main one.
• Never pull an electrical switch while it is under load.
• Never remove a fuse instead of disconnecting.
Lockout/TagoutApplication of LOTO Devices - 1910.147(d)(4)
• All energy-isolating devices are to be locked, tagged or both according to company’s Energy Control Plan.
• Only the standardized devices supplied by your employer are to be used for lockout/tagout, and they are not to be used for anything else.
• Use a lockout device if you lock cannot be placed directly on the energy control.• When lockout is used, every employee in the work crew must attack his/her personal lock.• More than one employee can lock out a single energy-isolating device by using a
multiple-lock hasp.• For big jobs, a lockout box can be used to maintain control over a large number of keys.• If tags are used instead of locks, attack them at the same point as you would a lock, or as
closed to it as possible.• Fill tags out completely and correctly.
Lockout/TagoutControl of Stored Energy - 1910.147(d)(5)
• Inspect the system to make sure all parts have stopped moving.• Install ground wires.• Relieve trapped pressure.• Release the tension on springs, or block the movement of
spring-driven parts.• Block or brace parts that could fall because of gravity.• Block parts in hydraulic and pneumatic systems that could
move from loss of pressure.
Lockout/TagoutControl of Stored Energy (con’t.)
- 1910.147(d)(5)• Bleed the lines and leave vent valves open.• Drain process piping systems and close valves to prevent the
flow of hazardous materials.• If a line must be blocked where there is no valve, use a blank
flange.• Purge reactor tanks and process lines.• Dissipate extreme cold or heat, or wear protective clothing.• If stored energy can reaccumulate, monitor it to make sure it
stays below hazardous levels.
Lockout/TagoutEquipment-Isolation Verification - 1910.147(d)(6)
• Make sure all danger areas are clear of personnel.• Verify that the main disconnect switch or circuit breaker can’t be
moved to the on position.• Use a voltmeter or other equipment to check the switch.• Press all start buttons and other activating controls on the equipment
itself.• Shut off all machine controls when the testing is finished.
Take any of the following steps that fit your company’s equipment and energy control program.
Lockout/TagoutRemoving Energy Controls
• Make sure the equipment is safe to operate.– Remove all tools from the work area.– Be sure the system is fully assembled.
• Safeguard all employees.– Conduct a head count to make sure everyone is clear of the equipment.– Notify everyone who works in the area that lockout/tagout is being
removed.
• Remove the lockout/tagout devices. Except in emergencies, each device must be removed by the person who put it on.
Lockout/TagoutRemoving Energy Controls (con’t.)
• In some workplaces, the last person to remove his/her lock may have extra duties.–He/she may have to remove the hasp and
lockout device.–Tags should be removed, signed, and turned in.– In some companies, the supervisor always
removes his lock last.• Follow a checklist of required steps to re-energize
the system.
Limitations of Tags1910.147(c)(7)(ii)
• Tags are essentially warning devices affixed to energy isolating devices, and do not provide the physical restraint on those devices that is provided by a lock.
• When a tag is attached to an energy isolation means, it is not to be removed without authorization of the authorized person responsible for it, and it is never to be bypassed, ignored, or otherwise defeated.
• Tags must be legible and understandable by all authorized employees, affected employees, and all other employees whose work operations are or may be in the area, in order to be effective.
• Tags and their means of attachment must be made of materials which will withstand the environmental conditions encountered in the workplace.
• Tags may evoke a false sense of security, and their meaning needs to be understood as part of the overall energy control program.
• Tags must be securely attached to energy isolating devices so that they cannot be inadvertently or accidentally detached during use.
Respiratory Protection• The basic function of a respirator is to reduce the risk of respiratory injury due
to breathing airborne contaminants. A respirator provides protection by removing the contaminants from ambient air or by supplying the wearer with an alternate source of clean breathing air.
• All respiratory apparatus are composed of two main parts:– the device which supplies or purifies air,– the facepiece which covers the nose and mouth and seals out the
contaminants. – The first component defines what class of respirator the device is; the
second determines the relative measure of protection afforded by that respirator.
1. Selection
2. Medical evaluation
3. Fit testing
4. Use
5. Maintenance and care
6. Breathing air quality and use
7. Training
8. Program evaluation
Respirator Program Elements
Respiratory Protection
Classifications of respirators:–Air purifying respirators (APRs)
• Particulate- mechanical filter• Gas and vapor- chemical cartridge• Requires knowledge of ambient concentration and
Maximum Use Limit (MUL) of the respirator• APRs only clean the air, the ambient concentration of
oxygen must be sufficient (19.5%) for the user
Air-Purifying Respirator (APR)
• An air-purifying respirator that uses a blower to force the ambient air through air-purifying elements to the inlet covering.
Respiratory Protection
Classifications of respirators:• Air supplying respirators (ASRs)
– Provide a substitute source of clean breathing air.– The respirable air is supplied to the worker from either
a stationary source through a long hose, or from a portable container.• The first type are called supplied-air respirators.
• The second type are known as self-contained breathing apparatus.
Supplied Air Respirator (SAR)• An atmosphere-supplying respirator for which the source
of breathing air is not designed to be carried by the user. Also called airline respirator.
Self-Contained Breathing Apparatus (SCBA)
• An atmosphere-supplying respirator for which the breathing air source is designed to be carried by the user.
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