Types of Confined Space | Confined Space Classification - NIOSH

In this article you will know about Types of confined space, NIOSH 89-106 is taken as reference for the classification of confined space.

What is Confined Space?

Confined Space refers to a space which is not designed for human occupancy, may have entry access and exit opening, hazardous atmosphere such as presence of toxic gases, flammable gase and may be subject to oxygen deficiency and oxygen enrichment. (Confined Space Types)

Types of Confined Space

As per NIOSH 89-106 confined space is classified in three classes.

1. Class - A - Confined Space.
2. Class - B - Confined Space.
3. Class - C - Confined Space.

Class A Confined Space

A confined space which have such atmospheric that can be Immediately dangerous to life and health (IDLH).

For Class A Confined Space rescue plan is mandatory, breathing support (SCBA) is mandatory for individual and a standby man and proper communication equipment also mandatory. (Classification of Confined Space)

Reason to IDLH atmosphere in Class A Confined Space

• Oxygen level - 16% or less
• LEL - 20% or above 

Class B Confined Space

A confined space which is dangerous and cause harm or illness if mandatory safety precautions not taken, but not IDLH. 

Rescue procedure is required for entry, breathing support and indirect or verbal communication equipment is mandatory.(what are the types of Confined Space)

Reason to Dangerous  in Class B Confined Space

• Oxygen level - 16% - 19.4%
• LEL - 10% - 19%

Class C Confined Space

A confined space with potential hazards which can cause harm but not dangerous neither IDLH.

Requires no modification of work procedure rescue procedure required and communication from outside of confined space mandatory. (How many classification of confined space)

Reason to potential hazards in Class C Confined Space

• Oxygen level - 19.5% - 21.4%
• LEL - 10% or less.

Following requirements are mandatory for all types of Confined Space

• Permit to work
• Gas test
• Training of workmen
• Rescue Plan
• Communication
• Rescue Equipment
• Complete Isolation & LOTO

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