August 2020 - Flammable Gas Covered By OSHA PSM

Aug 2020

Flammable Gas Covered by OSHA PSM

Flammable Refrigerants and Aerosol Can Propellants

What does increasing warehouse inventory of consumer sized aerosol cans and switching refrigerants to those with more flammable properties have in common? These are changes that can result in your facility needing to comply with OSHA’s Process Safety Management (PSM) regulation, 29 CFR 1910.119.

Category 1 Flammable Gas

When a Category 1 flammable gas is stored or used in excess of 10,000 lbs, the facility is likely covered by the PSM regulation. A Category 1 flammable gas is defined by the Hazard Communications Standard, 1910.1200 (c) and applies if either of these criteria are true (at standard testing conditions):

1. Lower Explosive Limit (LEL) is 13% or less in air


2. The explosive limit range of the gas range is 12% or more regardless of the LEL

Category 1 flammable gases are increasingly being used as automotive, appliance, and HVAC manufacturers are shifting towards low global warming potential (GWP) refrigerants. Category 1 flammable gas is also commonly used as propellants in aerosol can applications.

Relationship to the ASHRAE Safety Class

Flammable gas users are quick to point out that they use ASHRAE standards, including standard 34, as a basis to mitigate hazards. ASHRAE assigns letter and number designations to denote gas risk as high, medium and low based on several flammable properties. Requirements within the ASHRAE standard are risk-based, where higher hazard gases (A3 & B3, A2 & B2) have more requirements to follow and the lower flammability class (A2L & B2L) has more allowances.

The OSHA Hazard Communication standard makes determinations independent of the ASHRAE classification. Flammable gas that falls into ASHRAE safety class 3, 2, and 2L can be Category 1 flammable gas according to OSHA. The testing conditions and results are important, so read definitions carefully and do not mix testing to identify an ASHRAE safety class with criteria needed for OSHA's flammable gas criteria.

Protect Our Workers

The OSHA PSM regulation tries to minimize risk at facilities handling flammable and toxic materials. OSHA has published several interpretation and guidance documents to help companies understand the impact to both process facilities and warehouse operations.

PSM covered facilities must comply with fourteen elements, which include establishing systems for managing change, conducting process hazard analysis, establishing a mechanical integrity program, and following robust operating procedures. Importantly, the program must be created with contributions and engagement from impacted workers, and appropriate emergency response plans need to be created to ensure that local firefighters know how to respond to both the fire hazard presented by these materials and how to respond to the toxic byproducts they produce when they are burned.

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DEKRA Process Safety has decades of experience with hazardous materials and can help answer questions about refrigerant testing and changes your facility may need to make to comply with OSHA PSM. Contact us to meet with one of our specialists today.