Health & Safety

Indoor Air Quality Investigation: Formaldehyde Exposure Assessement

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 Phase I Investigation: HVAC and Initial Air Quality Survey

This photo shows the tracer gas testing to determine the room air-exchange rate in a laboratory specimen room. We also evaluated ambient formaldehyde and hydrocarbon (VOC) levels in this Phase I air quality survey. Two methods were used to determine the air exchange rate:

  1. by the classic method of taking "pitot tube traverse" measurements in the exhaust duct, which indicated an exhaust flow (Q) of 134 cubic feet per minute (cfm), or approximately 5 room air changes per hour;

2. by the "tracer gas concentration decay" method, which indicated 4.8 room air changes per hour. Both methods are in agreement.


air flow 1

   

 

Lapham 190A is maintained under negative pressure (i.e, air from outside this room enters rather than exits). Air primarily enters room 190 through the transfer grill in the hallway door. The air then exits through the ceiling exhaust grill, passes through circular duct to the roof mounted fan, and is finally exhausted directly to the outside of the building. Contaminants and foul-odors are not recirculated into the adjacent hallway or the building's common hvac ductwork.


air flow 2

 

 

 

The top photo shows the duct from the 190A ceiling exhaust grill; the latter photo show the duct-ascent to the roof penetration and fan unit. Duct traverse measurements indicated an exhaust value (Q) of 134 cubic feet per minute, or about 5 air changes per hour for this room.

air flow 4

 

 

 

 

This photo shows the location of the 190A exhaust fan and stack.


 

Phase II Investigation: Air Quality and Personal Exposure Monitoring

Additional air monitoring was performed and the Department of University Safety and Assurances is available to review and monitor work practices for the duration of this project. Material Safety Data Sheets (MSDS) are available through the Department of University Safety & Assurances Link Page, or through the Department of University Safety and Assurances.

Occupational Exposure Limits and Hygienic Values (1999): Formaldehyde (Formalin):

OSHA:
OSHA PEL-TWA (8-hour): 0.75 ppm
OSHA STEL (15 minute exposure): 2 ppm
OSHA Action Level: 0.5 ppm

NIOSH
NIOSH REL (8-hour): 0.016 ppm
NIOSH "Ceiling" (15 minute exposure): 0.1 ppm
IDLH: 20 ppm

ACGIH
ACGIH TLV "Ceiling": 0.3 ppm
ACGIH "A2" Suspected human carcinogen

Odor Threshold: 0.027 ppm to 9770 ppm, pungent (Source: various)

air results

  

 

 

Passive dosimeter (length-of-stain-tubes) were used on March 18, 1999. The average concentration in the specimen room was approximately 0.2 ppm (tubes #2 and #3, Sensidyne GasTech 91D Passive Dosi-Tube). Additional short-term area monitoring conducted February 24, 1999, had a similar result of 0.1 ppm (Dr�ger 0.2/a short-term tube).

The concentration directly outside the specimen room was below the limits of detection (tube #1), (73F, 35% RH).

Tony in a resperator

 

 

 

 

Respirator use during specimen disposal project. Cartridges are changed out every three hours as required by OSHA's Formaldehyde Standard.

Worker was monitored for potential exposure to formaldehyde.

Processing and proper disposal of the Lapham-South biological collections took approximately 15 hours of work: 2,522 pounds of specimens were processed, not including the specimens processed by Biological Sciences personnel. The preservatives, presumed to be low concentrations of formaldehyde and alcohol, was decanted off into the sewer. The specimens were washed with water, packaged and put in the dumpster. Some specimen bottles were "leakers", that required spill clean up. Air monitoring was conducted during the early phases of the project. No levels above that which the respirator was designed to handle was measured, even during the spill clean up incidents. However, exposure levels above the Permissible Exposure Limits (without regard to the respirator) were common. The choices of respirator, fume hood, disposal method and, especially, the good technique of the operator appears to have been sound for effective exposure control.

 

Updated November 16, 2007

 
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