OSHA CO2 Exposure Limits Added to Indoor Safety Alarm

co2 storage safety alarm

Why do we offer a 2 alarm and a 3 alarm version of our CO2 Storage Safety Alarm?

Some local municipalities have added the OSHA CO2 TWA (time-weighted average) exposure limits to bulk CO2 storage safety alarm specifications. To meet this requirement, CO2Meter offers the RAD-0102-6 which has 3 separate alarms.

CO2Meter first introduced our RAD-0102 CO2 Storage Safety Alarm with 2 separate alarms: 1.5% CO2 and 3% CO2. These alarm limits were developed to meet the needs of state and/or local fire codes. Most coded are derived from one or more of three sources:

  1. 2015 International Fire Code (IFC) Section 5307
  2. 2016 National Fire Protection Association (NFPA) 55, Compressed Gases and Cryogenic Fluids Code
  3. 2015 National Board Inspection Code (NBIC) Part 1 Supplement 3, Installation of Liquid Carbon Dioxide Storage Vessels

In addition, some codes are developed with input from the Compressed Gas Association (CGA) document G-6.5 standard for small (less than 1,000 lbs. stationary insulated carbon dioxide supply systems. Although the CGA codes are non-regulatory, CGA is recognized as an expert in the field so their suggestions are highly influential.

While the IFC, NFPA, NBIC and CGA requirements are all different, they tend to be generally the same. Most differences are the result of time-lags between jurisdictional adoption of the codes.

However, while the national codes are similar, the local codes are not. There are thousands of counties, cities, towns and local municipalities in the United States alone, and each has jurisdictional authority to create their own local codes. This is known as the “Authority Having Jurisdiction (AHJ)”.  As a result, any jurisdiction can require alterations to the codes as long as that alteration does not lessen the codes requirements.

OSHA CO2 Exposure Limits

In the case of the RAD-0102-6, this version of the CO2 storage safety alarm was designed to additionally meet the Occupational Safety and Health Administration (OSHA) time-weighted average (TWA) personal exposure limit (PEL) for CO2. The OSHA CAS No. 124-38-9 requirement says that the average CO2 level a worker can be exposed to over an 8-hour day can be no more than 5,000ppm, and that the short term exposure limit (STEL) can be no more than 30,000ppm (3%).

co2 storage safety strobes

To meet these OSHA requirements, a third alarm was added to RAD-0102-6. This alarm is fixed, and cannot be adjusted by the user.

In addition to adding the OSHA TWA requirements, some local municipalities require additional flashing strobes to increase the visual warning in the case of a high CO2 alarm. To meet this requirement, the RAD-0102-6 may be ordered with the optional strobe add-on package.  And, as codes continue to evolve, the strobes can be added at a later date as well.

Which CO2 Storage Safety Alarm is Right for You?

Before purchasing a CO2 storage safety alarm, it is important to know which standards your local municipality requires. In most cases this information can be obtained by either your local fire marshal or commercial building inspector.

Note that even if your local code does not require the OSHA 5,000ppm TWA alarm, it may be beneficial to your employees to have this feature. Over time, consistently high CO2 levels are associated with headaches, drowsiness, increased heart rate, nausea, and decreased employee concentration and decision-making ability. Except in an industrial setting, you should never see 5,000ppm TWA indoors.


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