Processes Involving Glutaraldhyde

New Exposure Standard

NZ OSH have changed the exposure standard for glutaraldehyde. In the 1994 edition of Workplace Exposure Standards, the exposure standard was a ceiling of 0.20 ppm. In the 2002 edition, the exposure standard is a STEL (Short Term Exposure Limit) of 0.05 ppm.

This change is likely to affect many processes involving glutaraldehyde. Total Air Care has tested such processes for several years and we have found that most processes tested complied with the ceiling of 0.20 ppm, but up to 50% would have had concentrations of glutaraldehyde in excess of 0.05 ppm.

Total Air Care will test to the new requirement immediately, so some processes that complied in the past will not comply now.

Accurate Testing Required

Total Air Care uses the PPM Glutaraldemeter to measure glutaraldehyde concentration. This meter will give a high reading if alcohol vapour is present. The meter can detect such distortion of the measurement by means of a “time to peak” function, so we know when a measurement is invalid. In the past, the presence of a little alcohol may have inflated the results a little, but the result was still less than the ceiling prescribed by OSH. But now, it will be very important to ensure that no alcohol is present at the time of testing. If alcohol is used in the process or in a cleaning operation, we recommend that it be removed from the area the day before the test is due and not used until testing is complete. Also, the air ventilation system should be left to run over-night to purge out any alcohol vapour.

Better Ventilation Required

Our experience has been that virtually all processes located within a fume cupboard or fume hood or recirculating fume cabinet achieved glutaraldehyde concentrations below the new 0.05 ppm STEL. Processes not contained within such a system may not now comply and the ventilation system may need to be upgraded before the system will comply.

In cases where the system does not comply, Total Air Care will recommend a solution. We can also direct you to suppliers of standard solutions (like fume cupboards) or assist directly with customised solutions.