This document provides information on confined spaces and confined space entry requirements. It defines a confined space, lists examples of confined spaces, and identifies potential hazards such as oxygen deficiency, combustible gases, toxic atmospheres, and mechanical or electrical hazards. It outlines permit requirements for confined space entry including procedures for isolating, ventilating, conducting pre-entry briefings, completing permits, atmospheric testing, and duties of entrants and attendants. Rescue and emergency services are required and proper PPE and training must be provided.

1. 29 CFR 1910.146
CONFINED
SPACE ENTRY

2. What is a Confined Space?
 Is large enough and so
configured that an employee
can enter bodily and perform
work;
 Has limited or restricted
means of entry or exit;
 Is not designed for continuous
human occupancy.
2
A space that:

3. Examples of Confined Spaces:
 Tanks
 Manholes
 Boilers
 Furnaces
 Sewers
 Silos
 Hoppers
 Vaults
 Pipes
 Deep excavations and
Trenches
 Tunnels
 Ducts
 Bins
 Pits
3

4. 4

5. Enclosed Water Tanks
5

6. 6
Pits

7. 7
Hoppers

8. 8
Fuel Tanks

9. 9

10. 10
Process
Tanks

11. 11
Tanker trucks are
also confined
spaces

12. Potential Hazards in Confined
Spaces
 Oxygen Deficiency
 <19.5% or >23.5%
oxygen concentration
 Combustibles
 Methane
 Hydrogen
 Acetylene
 Propane
 Gasoline fumes
 Toxic Materials
 Carbon Monoxide
 Hydrogen Sulfide
 Welding fumes
 Corrosives
 Electricity
 Mechanical Hazards
 Mixers
 Crushers
12

13. Hazards of Confined Spaces
• Oxygen Deficient Atmospheres
• Oxygen Enriched Atmospheres
• Flammable Atmospheres
• Toxic Atmospheres
• Mechanical and Electrical Hazards
• Temperature Extremes
• Engulfment Hazards
• Noise, Slick/Wet Surfaces, Falling Objects, rats
and snakes.
13

14. Oxygen Deficient Atmospheres
19.5 % Minimum acceptable oxygen level.
15 - 19% Decreased ability to work strenuously.
Impair coordination. Early symptoms.
12-14% Respiration increases. Poor judgment.
10-12% Respiration increases. Lips blue.
8-10% Mental failure. Fainting. Nausea
Unconsciousness. Vomiting.
6-8% 8 minutes - fatal, 6 minutes - 50% fatal
4-5 minutes - possible recovery.
4-6% Coma in 40 seconds. Death
14

15. Oxygen Enriched Atmospheres
• Oxygen level above 23.5%.
• Causes flammable and combustible materials to burn
violently when ignited.
• Hair, clothing, materials, etc.
• Oil soaked clothing and materials.
• Never use pure oxygen to ventilate.
• Never store or place compressed tanks in a confined
space.
15

16. Flammable Atmospheres
• 2 Critical Factors:
 Oxygen content in the air.
 Presence of a flammable gas, or vapor
 Presence of dust (visibility of 5’ or less)
• Proper air/gas mixture can lead to explosion
• Typical Ignition Sources:
 Sparking or electric tool.
 Welding / cutting operations.
16

17. Toxic Atmospheres
• Product stored in a confined space:
 Gases released when cleaning.
 Materials absorbed into walls of confined space.
 Decomposition of materials in the confined space.
• Work performed in a confined space:
 Welding, cutting, brazing, soldering.
 Painting, scraping, sanding, degreasing.
 Sealing, bonding, melting.
• Areas adjacent to a confined space.
17

18. Hydrogen Sulfide
• Decomposition of materials. Human waste.
• Rotten egg odor at low concentrations.
• Possibly no warning at high concentrations.
PPM Effect Time
10 ppm Permissible Exposure Level 8 Hours
50 - 100 Mild Irritation - eyes, throat 1 Hour
200 - 300 Significant Irritation 1 Hour
500 -700 Unconsciousness, Death 1/2 - 1 Hour
>1000 Unconsciousness, Death Minutes
18

19. 19
Carbon Monoxide
• Odorless, Colorless Gas.
• Combustion By-Product.
• Quickly collapse at high concentrations.
PPM Effect Time
35 Permissible Exposure Level 8 Hours
200 Slight headache, discomfort 3 Hours
600 Headache, discomfort 1 Hour
1000-2000 Confusion, nausea, headache 2 Hours
1000-2000 Tendency to stagger 1 1/2 Hours
1000-2000 Slight heart palpitation 30 Min.
2000-2500 Unconsciousness 30 Min.

20. Engulfment Hazards
• Loose, granular materials stored in bins and hoppers -
grain, sand, coal, etc.
• Crusting and bridging below a worker.
• Flooding of confined space.
• Water or sewage flow.
20

21. Other Hazards
• Noise
 Amplified due to acoustics within the space.
 Damaged hearing, affect communication.
• Slick / Wet Surfaces
 Slips and falls.
 Increased chance of electric shock.
• Falling Objects
 Topside openings expose workers inside confined space to
falling objects.
21

22. Testing The Atmosphere
• Verify presence of safe work atmosphere.
• Test all areas of a confined space.
 Top, Middle, Bottom
• Methane is lighter than air.
• Carbon Monoxide is the same as air.
• Hydrogen Sulfide is heavier than air.
• Oxygen Deficiency.
22

23. Test the Atmosphere
 Check for Oxygen Content:
 At least 19.5% and less than 23.5%
 Check for Combustibles:
 Less than 10% of the LEL
 Check for Toxic Gasses:
 Most commonly carbon monoxide (PEL <35 ppm)
 or any other hazardous materials as determined by
the use of the space.
23
In this order:

24. 24

25. 25

26. Ventilation
• First option to correct problems.
• Must be aware of hazards you are trying to correct in
the confined space.
• Air intake in a safe location to draw fresh air only.
• Continuous ventilation whenever possible.
• Retest the confined space before entry.
26

27. Ventilate the Space
 Use mechanical ventilation
 Fans
 Air horns
 Ventilate at the rate of at least
four (4) volumes per hour
 Larger spaces require more ventilation
 Make sure air supply is not
contaminated
 Ventilation air supply must be from
fresh air uncontaminated with
flammables, toxins, etc.
27

28. 28

29. Permit-Required Confined Space
 A Permit-Required
Confined Space is
confined space that
has one or more of
the following
characteristics:
 Excavation more than 1.2 meter
deep are treated as ‘Confined
Spaces
 Contains or has the potential to
contain a hazardous atmosphere;
 Contains a material that has the
potential for engulfing an entrant;
 Has an internal configuration
such that an entrant could
become trapped or asphyxiated;
or
 Contains any other serious safety
or health hazard.
29

30. Permit Required Confined Space
30
Required Elements:
Written Program
Space Specific Entry Procedures
Training
Duties of Authorized Entrants
Duties of Attendants
Duties of Entry Supervisors
Rescue and Emergency Services
Employee Participation

31. Permit-Required Confined Space
Entry Procedure
 Isolate the space
 Ventilate the space
 Conduct Tailboard
 Complete permit
 Test the atmosphere
 Enter the space
31

32. Isolate the Space
from all hazards
 Close Valves
 Double block & bleed, or
 Blank flange
 Empty the Space
 Depressurize, vent & drain
 Lockout/Tagout Equipment
 Electrical sources
 Rotating/reciprocating parts
 Hazardous materials
 Clean residue from the space
32

33. Isolation
Lockout/Tagout
Blinding/ De-blinding
Double Block and Bleed
33

34. Ventilate the Space
 Use mechanical ventilation
 Fans
 Air horns
 Ventilate at the rate of at least
four (4) volumes per hour
 Larger spaces require more ventilation
 Make sure air supply is not
contaminated
 Ventilation air supply must be from
fresh air uncontaminated with
flammables, toxins, etc.
34

35. Examples of Positive Ventilation
35

36. Positive Ventilation System
36

37. Other Control Techniques
Inerting (Note: Inerting with a gas such as
nitrogen or carbon dioxide will result in an
oxygen deficient atmosphere)
Flushing
37

38. Conduct a Tailboard Briefing
 Entire crew must attend
 Attendants, entrants, entry supervisor
 Review hazards of entry and work
 Review PPE
 Review procedure for contacting rescue
 verify rescue available
 Complete permit
38

39. Complete Entry Permit Form
 Permit must be correctly and
completely filled out prior to entry.
 Permit must be activated by Entry
Supervisor’s signature to be valid.
 No entry is allowed without a valid
permit.
 Permits are valid for up to one shift.
 When work is completed, permit and
tailboard form should be returned to
issuer.
 Closed permits must be kept on file.
39

40. Test the Atmosphere
 Check for Oxygen Content:
 At least 19.5% and less than 23.5%
 Check for Combustibles:
 Less than 10% of the LEL
 Check for Toxic Gasses:
 Most commonly carbon monoxide (PEL <35 ppm)
 or any other hazardous materials as determined by
the use of the space.
40
In this order:

41. NOTICE:
 Any time a limit is exceeded, no matter
what the reason, all personnel shall
immediately exit the space, and no
others shall enter until atmospheric
conditions are returned to safe levels.
41
THERE ARE NO EXCEPTIONS TO THIS!

42. Atmosphere Testing Shall Be
Performed:
 Prior to every entry when the space is vacant;
 After a 10 minute ventilation period (if ventilation
is necessary);
 At least hourly for permit-required confined
spaces.
 More frequently, if conditions or suspicions
warrant.
42

43. Confined Space Entry
43
Means of emergency rescue
must be readily available
to the confined space
entry attendant for
emergency
extrication of
entrants.

44. Enter the Space and Proceed
with work:
 An attendant shall be posted near the
entrance for the duration of the work. He
shall be in constant communication with
the entrants while the job is in progress.
 All entrants shall sign the sign in log when
entering the space and sign out when
exiting.
 The attendant shall maintain the permit
and sign in log for the duration of the work.
44

45. 45

46. 46

47. 47

48. Confined Space Entry
48
The attendant should
attempt to remove the
entrant from the confined
space using tripods, hoist, and
lifelines. Attendants are NOT
TO ENTER CONFINED
SPACES. Lethal hazards may
be present within the confined
space. Only properly equipped
and trained emergency rescue
personnel may enter confined
spaces to make rescues.

49. 49

50. 50

51. 51

52. When the Job is Done:
 Remove all personnel, tools, and debris from
the space. Sign off the log.
 Close the space.
 Close the permit.
 Review the job with the host employer
(hazards, problems, other employers, etc.)
52

53. Entrant Responsibilities
 To assure that the space has been adequately
ventilated, isolated, emptied, or otherwise
made safe for entry.
 To immediately exit a space, without question,
upon word of the attendant, no matter what
the reason.
 To follow all safety rules and procedures that
apply to the job.
 To be familiar with the work to be performed
and the procedures that apply to the job.
 To use the appropriate PPE whenever
necessary.
53

54. Attendant
An individual stationed outside one or more
permit spaces who monitors the authorized
entrants and performs all attendant’s duties
assigned in the employer’s permit space
program
54

55. Duties of Attendants
Knowledge of the hazards of the space
Aware of possible behavioral effects of hazard
exposure in authorized entrants
Continuously maintains an accurate count of
authorized entrants
55

56. Duties of Attendants
Remains outside the space during operations
until relieved by another attendant
Communicates with authorized entrants
Monitors activities inside and outside the
space
56

57. Duties of Attendants
Summons rescue and other emergency
services
Performs non-entry rescues as specified by the
employer's rescue procedure
Performs NO duties that might interfere with
monitoring and protecting the entrants
57

58. Supervisor Responsibilities
 To assure adequate protection is
provided to the entrants by verifying
adequate lockout/tagout and that all
hazards are securely isolated.
 To support the attendant’s authority in
controlling access to a confined space.
 To verify that all personnel have exited
prior to closing the space.
 To assure that all personnel involved are
aware of the hazards associated with the
space.
 To assure that rescue services are
available prior to entry.
58

59. 59

60. 60

61. 61