Carbon monoxide controls for supplied breathing air

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

March 3, 1986

Mr. Anthony W. Ferroni
Vice-President
Survival Air Sales Co., Inc.
[Recipient address omitted]
Dear Mr. Ferroni:

This is in response to your letter of January 24, requesting clarification concerning carbon monoxide from oil-lubricated compressors normally found in automobile paint and body shops.

I will answer your questions in the order that you presented them in your inquiry to me.

1. A. What type of high heat temperature alarms are recommended?

[29 CFR 1910.134(i)(7)] does not state a specific type of high heat temperature alarm that must be used. Contact the manufacturer(s) for recommendations on these compressors.

Is a snap disc high heat temperature sensor switch, activating a horn or light, sufficient?

Since [29 CFR 1910.134(i)] does not state a specific type, an alarm system that meets manufactures recommendations and meets our requirements in [29 CFR 1910.134(i)] would be acceptable.

What is the DB requirement on such a horn?

OSHA does not have a specific dB requirement for such a horn alarm; however, the horn alarm must be loud enough to be heard by the employees using the compressor. The horn alarm also must meet the noise requirements of 29 CFR 1910.95, Table 0-16 - Permissible Noise Exposures.

B. Where would a high heat sensor be mounted? Would more than one be required?

OSHA does not specify where these high heat sensors should be mounted and if more than one would be required. Contact the manufacturer(s) for recommendations on mounting and additional heat sensors.

2. Would an oil-lubricated compressor, used for the breathing air source, be approved by OSHA following these parameters?

A. Two snap disc heat sensing switches mounted on the compressor cylinder head activating an alarm horn.

OSHA standard [29 CFR 1910.134(i)] does not state where to place these switches or how many should be used as mentioned in 1.B., above. Contact the manufacturer(s) of these compressors for this information.

B. An in-line air filtration system that removes oil, water, particulates and objectionable tastes and odors to meet Grade D air quality requirements (does not remove carbon monoxide).

This in-line air filtration system does not meet Grade D air quality if more than [10 ppm] of carbon monoxide is present [(i)(6)] ; however, this filtration system can be used to remove the other substances, tastes and odors.

C. Initial weekly system checks for carbon monoxide, and monthly checks thereafter using the stain tube method for detecting carbon monoxide in the system [10 ppm, (i)(6)].

Because the length of stain tubes is no longer certified by NIOSH, they may be used only as a screening device.

D. Using a carbon monoxide color-change dot mounted inside a full face air-supplied respirator for visual check for CO detection in high concentration. The color dot...

The carbon monoxide color-change dot should not be used alone but only as a screening device.

E. Would OSHA recommend the use of a synthetic oil in the compressor rather than hydrocarbon type oils?

If there is no chance for carbon monoxide production from oil breakdown and it satisfies the manufacturer's requirements, synthetic oils can be used.

We also need clarification concerning proper respirator recommendations for paint spray products...

Due to extreme toxicity and lack of odor warning properties, only positive-pressure supplied air respirators are acceptable. Full facepiece is required if eye irritation is experienced by the respirator wearer.

Since no negative pressure respirator (air-purifying respirator) is recommended for use with isocyanates would a powered air system such as shown in the sample be approved? (See enclosed #3.)

Powered air purified respirators could not be used for protection against isocyanates.

If you have any further questions, please contact us.

Sincerely,

Edward J. Baier
Director
Directorate of Technical Support

[Requester letter reproduced on OSHA page; omitted here.]