Indoor Environmental Quality (IEQ) has fast been becoming a critical issue to office workforce over the last ten, fifteen years as office workers generally spend much longer time working indoor than ever before. Favorable IEQ not only contributes significantly to the wellness of the workforce, it also enhances effectiveness and productivity. As previously mentioned in a Safetywise article in March (http://epublish.ust.hk/cgi-bin/eng/story)
on issues about moving in to a new campus building, HSEO has initiated a pre-occupancy IEQ survey in the Lee Shau Kee Business Building (LSKBB) at the beginning of May to assess several IEQ parameters such as formaldehyde, total volatile organic compound(TVOC), potable water, radon, and electric/magnetic field strength. The survey is still in progress but initial survey results have provided a promising start towards the goal of achieving a satisfactory IEQ before occupancy.
TVOC and Formaldehyde
Early results from the analysis of the air samples collected for formaldehyde survey showed no reading approaching the preset acceptance criteria of 0.3 ppm, which is the Occupational Exposure Limit set by the HKSAR Labour Department. The overall average of the 24 samples collected was 0.018 ppm with the highest of 0.036 ppm being recorded. TVOC levels at 9 sampling locations were monitored. The overall average was 0.39 ppm with 0.53 ppm being the highest reading reported. The result was within the preset acceptance criteria of 1.3 ppm, which is a Canadian reference level for building occupancy. As majority of the furnishing materials used in the LSKBB is solvent free, TVOC level in the LSKBB is comparatively lower than new buildings using non-solvent free furnishing materials. Walk-through inspection with TVOC detector during the laying of carpet and furniture installation also revealed no significant increases in TOVC level in the building. Both formaldehyde and TVOC levels in the building are expected to drop further with time after occupancy.
Water samples were collected from all the pantries and potable water outlets for water quality analysis. Heavy metals contents such as lead, cadmium, nickel, etc., in the potable water samples were assessed. In addition, sulphate, nitrate and bacterial contents were analyzed in selected samples. Since, from past experience, sulphate, nitrate and bacterial levels found in the water samples were very consistent across different sampling locations, a smaller number of samples will be adequate for assessment. On the other hand, heavy metal contents in water samples may vary considerably from tap to tap, all water outlets were, therefore, surveyed. The results reported for heavy metal contents in the water samples so far are well within the acceptance criteria which is the standard for drinking water established by the World Health Organization. The only exception is one water sample collected from a drinking fountain at the ground floor which contains a lead content slightly higher than the established limit. Thorough flushing of the fountain will be conducted to reduce the lead content to an acceptable level. Results for other potable water tests are not available at this time and will be reported later.
Assessment on occupants' exposure to electric/magnetic field strength generated by power cable, wireless access point and mobile antenna revealed no exposure higher than the current standard allowed. The highest field strength recorded for occupants' exposure to extremely low frequency (from power cable) was found to be less than 0.2% of the applicable limit. The highest exposure reading of 0.0055% of the limit allowed was recorded for occupants' exposure from 27 MHz to 3GHz microwave (covering telecommunication wavelength). Occupants' exposure to electromagnetic field is not expected to vary significantly after occupancy. Spot check will be conducted for confirmation after moving in.
Radon concentrations in offices on the fourth, fifth and sixth floors were assessed. The radon level reported from 8:00 am to 10:00 pm for 9 sampling locations varied from 28 Bq/m3 to 93 Bq/m3. The results reported satisfy the existing acceptance criteria established by the University, which is less than 150 Bq/m3 from 8:00 am to 10:00 pm. However, the ventilation system is still under testing and commissioning. There may be variation in performance when the system is set for routine operation. Further radon monitoring in LSKBB will continue until the testing and commissioning phase is completed and the routine ventilation schedule is implemented.
A final report will be produced when the other survey results are available. HSEO will continue to monitor various IEQ factors after occupancy and to ensure the IEQ objectives be met continually.