Final report: Indoor Air Quality Assessment of Northern Territory Remote Accommodation Containers
Project Reference CN080411 Prepared By Cetec
Department of Families, Housing, Community Services and Indigenous
Affairs (FaHCSIA)
June 2008
Contents
- 1 Executive Summary
- 2 Introduction
- 3 Background to Indoor Environment
- 4 Indoor Environment Assessment
- 5 Additional Observations
- 6 Conclusions and Recommendations
- Disclaimer and Copyright
1 Executive Summary
Cetec Pty Ltd has conducted an indoor air quality assessment at the Department of Families, Housing, Community Services and Indigenous Affairs (FaHCSIA) Northern Territory remote accommodation containers. Testing was carried out in 297 containers and demountables over 59 sites. Air pollutants were taken using real-time monitors and laboratory analysis of chemical air samples. Chemical analysis and compilation of results was carried out by Foray Laboratories Pty Ltd. Measurements were taken in the containers and compared to ambient conditions. Measurements were also taken under the beds, inside wall insulation, under floor vinyl, in bathrooms and inside cupboards in an attempt to isolate the source of the emissions.
Our initial measurements and observations based on indoor air quality indicate the following:
Indoor air quality parameters measured included total volatile organic compounds (TVOC), formaldehyde (HCHO), carbon dioxide (CO2), carbon monoxide (CO), ambient airborne microbials, temperature and relative humidity. Initial results indicate that the majority of containers tested were above the exposure limits for certain contaminants including CO2, TVOC, and HCHO.
In view of the stated results and findings, the following conclusions can be made, based on health limits for TVOC and formaldehyde used in this report by CETEC following consultation with National Industrial Chemicals Notification Assessment Scheme (NICNAS). The other parameters are based on Cetec’s assessment.
- Overall, 86% of FaHCSIA containers are over the Environment Australia (EA) and NICNAS/ National Health and Medical Research Council (NHMRC) formaldehyde threshold values and 3% are between the NHMRC and EA limits. Since only 3% are between NHMRC and EA limits, 83% of containers should not be occupied for any timeframe until verified remediation has occurred. Occupation is acceptable for 11% of FaHCSIA containers.
In detail, the TVOC distribution for containers shows that 71% are unoccupiable, 9% manageable by occupants and 20% occupiable without requiring management or remediation, as shown below.
- The formaldehyde distribution for containers indicates that 80% are unoccupiable and 20% are occupiable without remediation as shown below.
- The seventeen (17) un-tested Kitchen containers should either be classified as un-occupiable and remediated or tested to confirm contaminant levels.
- Tendency for CO2 and VOC to build up rapidly within the accommodation indicates a need for increased ventilation.
- To control excessive TVOC and formaldehyde levels, remediation will be needed but only after thorough research and trials on selected accommodation containers, according to the supplied Cetec proposal.
- We would anticipate remediation of containers to include (but not limited to) the installation of either active or passive ventilation, ventillation of products responsible for emissions, air-conditioner modifications, air-conditioner filtration and/or removal of products contributing to emissions.
- Ventilation must account for the emission rate of VOC from internal materials, as materials will continue to emit at a rate that can contribute to above-limit ambient VOC levels close to emitting materials, even if ventilation is improved. Consequently, occupants close to emitting materials, such as walls, bedding or desks, may still be exposed to above-limit VOC levels if ventilation is not configured and modeled correctly.
- Variability of VOC and formaldehyde results highlights the requirement for investigation into the conditions causing the variation.
- High VOC readings on real-time monitors when recorded near fit-out materials such as unwrapped mattresses, beneath vinyl flooring and wall insulation.
- Stronger odour was noted on some containers not yet occupied and those that had been kept closed for longer period of time.
- VOC and formaldehyde results were not significantly dependent on container temperature and humidity during testing indicating that release of contaminants is controlled by diffusion and hence remediation cannot be by surface chemical or heating treatments.
2 Introduction
From 14 April to 14 May 2008, Cetec Pty Ltd was engaged to conduct an Indoor Air Quality (IAQ) Investigation of 294 converted shipping container accommodation units across the Northern Territory (NT). The accommodation is used to house a range of Federal and State Government staff including Indigenous Intervention Government Business Managers (GBMs), Community Employment Brokers (CEBs) and Police.
The IAQ investigation included the measurement of various indoor air quality parameters including measurements taken using real-time devices and sorbent tube sampling analysed by laboratory methods.
Figures 1 & 2. Typical accommodation container configuration and fit-out.
Containers and demountables varied in fit-out and age. A typical accommodation setup for GBM’s consisted of four bedroom containers, a kitchen container and an office container. These containers opened out onto a covered communal area. For Police, a typical set up included bedroom containers, office containers, a kitchen container, laundry container and a holding cell container.
This report makes conclusions and recommendations only for FaHCSIA accommodation containers.
3 Background to Indoor Environment
An individual’s performance can be affected by factors including the working environment, personal motivation and the ability to perform a job. The working environment comprises indoor climate, such as temperature, ventilation, noise, lighting, the facility services like cafeteria and mail service as well as infrastructure like workstation layout, landscaping.
Research and practice has shown that that the ideal office environment requires comfortable temperature and humidity, an adequate supply of clean outdoor air, appropriate air distribution within the space, low levels of contaminants, and good communication between building occupants and building operators.
Figure 3 shows the parameters typically associated with the indoor environment. Most of these indoor environment parameters can be quantitatively measured, while others either cannot yet be fully assessed or assessed at all by quantitative measurements. In the latter case the parameters can be of a subjective nature and/or involve many interacting variables so the perception of occupants through occupant satisfaction surveys provides the direct or indirect means of evaluation.
Figure 3: Components of indoor environment
3.1 Thermal Comfort
Comfortable thermal conditions in mechanically ventilated buildings depend on the temperature, air velocity, and relative humidity in the space, occupant activity level and clothing insulation. These factors affect the human body’s physiological processes (such as sweating and shivering), and therefore influence whether the body has a comfortable thermal state. Thermal comfort requires comfortable overall thermal sensations and also comfort on particular body parts.American Society for Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) has established overall temperature and humidity recommendations that create thermal comfort. ASHRAE 55: “Thermal environmental conditions for human occupancy”, is considered the major reference document for thermal comfort. Figure 3 provides acceptable operating temperatures as specified by ASHRAE 55.
| Conditions | Acceptable Operative Temperatures a,b | |
|---|---|---|
| Summer | Relative Humidity 30% | 24.5-28°C (76-82°F) |
| Relative Humidity 60% | 23-25.5°C (74-78°F) | |
| Winter | Relative Humidity 30% | 20.5-25.5°C (69-78°F) |
| Relative Humidity 60% | 20-24°C (68-75°F) | |
a: Assumes sedentary office activities and air velocity less than 0.2 m/s (40fpm). b: Operative temperature is a combination of air temperature and radiant temperature. For relatively uniform environments, radiant temperature is equal to air temperature. Based on: ASHRAE (2004). |
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Table 1: Acceptable operating temperatures as specified by ASHRAE 55.
Due to the number of interacting variables it is considered not possible to satisfy the thermal preferences of more than 80 to 90% of the occupants of even a static building under the best of circumstances. ASHRAE 55 thus recommends comfort requirements “known to be acceptable to at least 80% of the occupants”. Assessment of comfort for field installations in extreme climates is not well researched. However it is intuitive and practically observed that occupants that are required to work in extreme conditions such as the tropics or in desert environments such as those encountered throughout the Northern Territory do require good quality accommodation for part of their working day and all of their resting day. During the working day, cerebral tasks such as report writing, planning and external communications require the sort of environment considered satisfactory for good city offices. For the resting periods, they require private, peaceful and comfortable conditions. It is well known that stressed persons become more physically and psychologically sensitive to inadequate indoor environmental conditions such as noise, lighting, comfort and pollutants. Both work and personal productivity and wellbeing suffers and stress then snowballs.
Research shows that a hot or cold environment reduces comfort and task performance. Hot environments can also cause fatigue, difficulty concentrating, headaches, and perceptions of poorer IAQ. Occupants typically prefer moderate temperatures.
Humidity is desirable. Without it, occupants can experience problems with dry eyes, nose, throat or skin, and static electricity. However, excess humidity is also problematic because it increases the risk of infection, promotes mould and bacteria growth, and amplifies discomfortFigure 4 shows preferred humidity bands for a range of factors. The optimum range appears to be 40 to 60%, though 30 to 60% is considered acceptable for human comfort. Air-conditioning generally reduces humidity but, in some cases, it can cause localised condensation and then microbial and chemical emissions.
Figure 4: Optimum humidity range as per ASHRAE Systems Handbook
Draught is local air movement that cools an occupant uncomfortably and is the most common form of local thermal discomfort. The discomfort from draught depends on temperature, air velocity and the amount of fluctuation in the airflow. People are particularly sensitive to draughts at the head and ankles. The risk of draught can be minimised by maintaining air velocity below 0.2 metres per second (m/sec) and by directing the air supply away from occupants (ASHRAE 55). This can be difficult in restricted spaces as those found in field accommodation.
In this study thermal comfort was evaluated using a real time portable device known as a Q-Trak Indoor Air Quality monitor to simultaneously measure air temperature and relative humidity.
3.2 Air Quality
Studies have shown that people generally spend as much as 90 percent of their time indoors and therefore, the condition of indoor air has a vital impact in human health. In this study, the occupancy patterns were complex since the FaHCSIA and Police complexes were designed to provide flexible accommodation for regular and itinerant workers, offices, storage and communal areas The periods and functions of occupation and operation varied. Like most modern buildings, the NT Intervention complexes were designed to be airtight for extreme weather conditions and to save energy, resulting in less fresh air intake and a general build up of pollutants in the indoor environment.
One or all of chemical, biological and particulate indoor pollutants affect air quality and the acceptance of the indoor environment to varying degrees by different occupants. These pollutants will be discussed briefly in turn.
3.2.1 Volatile Organic Compounds
The term “organic compounds” covers all chemicals containing carbon and hydrogen. The World Health Organisation (WHO) defines volatile organic compounds (VOCs) as organic compounds with boiling points between 50°C and 260°C, excluding pesticides. The term encompasses a very large and diverse group of carbon-containing compounds. There are probably several thousand chemicals, synthetic and natural, that can be called VOCs. Of these, over 900 have been identified in indoor air, with over 250 recorded at concentrations higher than 1 part per billion ( about 1 microgram per cubic meter).
Recent studies conducted, for example, as part of the State of Washington's East Campus Plus Program1 showed that 96 percent of the VOCs found in a large office building following construction resulted from the materials used to construct and furnish the building. Contributors included hard surface and carpet flooring materials, paints, adhesives and sealants, office furniture, computers, insulations, vinyl wallcoverings, ceiling tile, cabinetry, fireproofing, and textile furnishings.
Occupants themselves, their work and personal activities such grooming, insect control and deodorising sprays contribute to VOC’s, especially if ventilation is inadequate. In some environments, the quality of the external air affects the indoor environment. This can be direct such as from industrial or nearby construction or maintenance activities
The health effects of exposure to VOCs in the non-industrial indoor environment range from sensory irritation at low/medium levels of exposure to toxic effects at high exposure levels. As VOCs belong to different chemical classes the severity of these effects at the same concentration level may differ by orders of magnitude. When many pollutants are present at low concentrations, their possible combined human health effects are difficult to predict based on present toxicological knowledge. Cross reaction between compounds and surfaces is becoming understood and can complicate assessments. Hence the best rule is to minimise the accumulation and levels of TVOCs.
The consensus of many researchers is that a recommended limit of 0.5 milligrams per cubic metre (mg/m3or 500 micrograms per cubic meter) is appropriate and achievable for total low toxicity VOCs in occupied environments. Some special compounds known as carcinogens or high irritants should be restricted to well below this limit. In the cases where specific unusual but known VOC’s contaminate the environment, relevant risk assessments should be carried out to determine prudent safe limits.
For the NT Intervention complexes, discussions on appropriate regulatory standards for airborne contaminants based on health considerations were held between Dr Vyt Garnys of Cetec and the National Industrial Chemicals Notification and Assessment Scheme (NICNAS) who were appointed by FaHCSIA as their independent advisors for VOC health limits. The relevant Australian National Health and Medical Research Council (NH&MRC), NICNAS, Environment Australia (EA) and World Health Organization (WHO) advisory limits formed the basis for the assessments by Cetec of the recommended limits for VOC to be used in this report
The two key contaminants relevant from the findings of this report are Total Volatile Organic Compounds and Formaldehyde.
These will be considered in turn, keeping in mind that both contaminants co-exist as a mixture in the container air. The synergistic effects of these contaminants have not been considered but are likely exist to some varying degree for some persons.
A summary of guideline limits and risks is as follows:
Table 2: WHO2 Exposure Levels
| Organic Compound | Maximum Permissible Limit (microgram/m3) |
|---|---|
| Vinyl Chloride | 1 |
| Benzene | 17 (1 x 10-4 – health risk) |
| Toluene | 1000 (30 min average) |
| PAH | 0.0012 (1 x 10-4 health risk) |
| Styrene | 70 (30 min average) |
| Formaldehyde | 100 (30 min average) |
| Butadiene | 10-20 (smoky environments) |
In Australia, recommended indoor limits were set by the NHMRC until about 2006 as shown below.
Table 3: Previous NHMRC Recommendations for IAQ
| Organic Compound | Microgram/m3 |
|---|---|
| TVOC | 500 |
| Any single compound | 250 |
| Formaldehyde | 100 |
2 World Health Organization (WHO): Air Quality Guidelines for Europe, Second Edition, 2000
After 2006, EA agencies such as The Environmental Protection Heritage Trust (EHPT) and the NEPSI and NEPM processes recommended Indoor air limits for toluene and xylene as shown below.
Table 4: Current EA/ EPHC Recommendations for IAQ
| Organic Compound | Microgram/m3 |
|---|---|
| Toluene | 1000 |
| Xylene | 250 |
After consideration of the above limits and the compounds likely to be present in the NT Intervention container accommodation, CETEC determined, following consultation with NICNAS, that a conservative assessment for acceptable accommodation air quality without the need for further control should be based on the NHMRC 2006 guidelines as above. This would accommodate the NICNAS recommended formaldehyde level of 80 ppb, or approximately 100 micrograms per cubic meter. If appropriate occupant control measures to further ventilate the accommodation and conduct reassurance monitoring were possible, the limit could be broadened to 1000 micrograms per cubic meter TVOC and 100 micrograms per cubic meter formaldehyde.
Total VOCs was determined by using active sorption methods based upon ISO 16200-2 (2000): “Workplace air quality – sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography”.
Cetec measured VOCs with active absorption onto activated carbon and XAD7 chromatographic resin and then analysed by GCMS and reported as TVOC in toluene units. Indicative field measurements used a PPB Rae instrument based on photo-ionization detection (PID).
3.2.2 Carbon Monoxide
Carbon monoxide is a toxic, odourless, tasteless and colourless gas. The typical source for carbon monoxide in an office is exhaust from combustion engines. The vehicular activities in the immediate vicinity of the building may lead to the ingress of exhaust into the building.
The recommended limit for carbon monoxide is given by WHO as 10 parts per million (ppm) for an eight hour time weighted average.
The level of carbon monoxide was directly measured with a real time portable device known as a Q-Trak Indoor Air Quality monitor.
3.2.3 Formaldehyde
Formaldehyde is a colourless gas with a pungent odour. Formaldehyde is an important chemical used widely by industry to manufacture building materials, fabrics, cleaning fluids and numerous other household products. Formaldehyde can also be a by-product of combustion and certain other natural processes.
Exposure to formaldehyde produces irritation of eyes, nose and throat, headaches and dizziness. Since 2004 formaldehyde has been classed as a human carcinogen. World Health Organization (WHO): Air Quality Guidelines for Europe, Second Edition, 2000 is indicates that to prevent significant sensory irritation in the general population, an air quality guideline value of 0.1 mg/m3 ( 100 micrograms per cubic meter) as a 30-minute average is recommended. Since this is over one order of magnitude lower than a presumed threshold for cytotoxic damage to the nasal mucosa, this guideline value represents an exposure level at which there is a negligible risk of upper respiratory tract cancer in humans. As noted in Section 3.2.1 above, This is also the limit proposed by NICNAS and NHMRC.
Formaldehyde was measured using handheld monitors and active absorption onto silica (SKC treated DNPH silica gel tube) or treated XAD-2 tubes, and analysed via HPLC or GCMS. An instant indication of Formaldehyde levels was also obtained using Kitagawa indicator tubes.
3.2.4 Airborne Microbials
The three common types of microbiological contaminants found in buildings are bacteria, fungi (moulds and yeasts) and viruses. Micro-organisms are present in every environment found on the surface of the earth. In buildings, microorganisms are generally found on surfaces (such as carpet, ceiling, tiles), within the building water systems, as well as floating within the airspace on dust and aerosol particles.
In air-conditioned buildings, water or condensation in ventilation systems can act as breeding grounds for bacteria, which are then dispersed through the ventilation process. The presence of bacteria in the environment does not necessarily imply that human infections will occur.
Common causes of fungal growth in buildings are condensation on improperly insulated air ducts, water damage on carpets, rain entering an inadequately sealed building and accumulation of moisture on building surfaces. Fungi require nourishment, as well as moisture, to proliferate. They can obtain nutrients from almost all common construction materials and also from dirt on surfaces.
Viruses do not survive long in mechanical ventilation and air conditioning systems and do not replicate inside the system. Viral infections such as colds or influenza are normally transmitted from person to person via aerosols of body fluids.
A recommended limit has not been established as presently available knowledge does not permit setting threshold limit values for the presence of airborne bacteria in non-industrial indoor environment. As rules of thumb there should be no amplification of indoor microbial levels above outdoor levels and typical occupied offices have less than 500 cfu/ml.
Airborne microbials as a total of airborne viable mould and airborne viable bacteria is determined using the principle of the inertial impactor as described by NIOSH 0800: “Bioaerosol Sampling (Indoors)”. Different culture media were used for mould (e.g. malt extract) and bacteria (e.g. blood agar). The measurement units were colony forming units per millilitre (cfu/m3). I this study, due to limitations of time at remote locations, settlable microbials were collected separately on the bacteria and fungal media and classified after incubation.
3.2.5 Carbon Dioxide
Carbon dioxide should not be considered as an indoor pollutant but instead a measure of ventilation effectiveness. Mechanical ventilation provides outdoor air to the office to dilute contaminants; it also creates the air movement that forces supply air to circulate and old air to be removed via the return air grilles. Dilution and removal are essential for contaminant management, good indoor air quality and occupant comfort. Office spaces need to be ventilated with sufficient outdoor air to dilute and remove contaminants and provide occupants with clean air to breathe.
Elevated levels of carbon dioxide indicate an insufficient amount of fresh, outdoor air is being supplied to the occupied area of the building. As carbon dioxide is an unavoidable, predictable and easily measured product of human occupancy, it can be used as a marker for ventilation effectiveness.
Carbon dioxide can cause health effects at high levels; e.g. 5000 ppm (NOHSC TWA) but a comfort level of 1000 ppm maximum is recommended in ASHRAE 62. Alternatively, ventilation effectiveness can be assessed by considering the difference between indoor carbon dioxide levels and background (outdoor) carbon dioxide levels. This follows the outcomes of the Austrian working group on indoor air and divides air quality into five categories (high, good, fair, poor and very poor)3.The level of carbon dioxide was directly measured with a real time portable device known as a Q-Trak Indoor Air Quality monitor.
3 Hutter HP, Moshammer H, Wallner P, Tappler P and Kundi M (2006). Carbon dioxide; Indoor air quality guidelines from the Austrian Working Group on indoor air. Abstracts Healthy Buildings 2006, Lisbon pp133
4 Indoor Environment Assessment
4.1 Indoor Environment Quality
Measurements involving portable real-time instruments were conducted. Results for individual sites are provided in spreadsheets with filenames in the F080422 Minjilang 150408.xls format. Each indoor environment parameter is presented as an average of the collected data from each container.
Real time measurements by field hand held instruments were in almost all cases significantly lower than the reference method using integrating pumped air through sorbent tube with subsequent laboratory measurements.
The real-time field measurement is useful for immediate indications of airborne levels of the major contaminant compounds and for tracking high emission sources in different parts of the room.
Field measurements cannot be used contractually or legally since they are not certified reference methods and, for this project were instantaneous readings due to time and numerous location requirements at each site.
In contrast, the adsorbent/laboratory methods are certified, integrate over a more representative period, are more sensitive and are able to show the presence of individual compounds if the data is further analysed. Additionally, in some cases, the 2 hour sampling/adsorbent/laboratory method may have collected more TVOC due to the additional accumulation of chemical pollutants over the 2-3 hour sampling period after the container door was closed, as suspect materials are continually emitting.
Real time measurements were taken shortly after entering the accommodation containers. The action of opening the door would dilute to a greater or lesser extent the volatilised (airborne) organic compounds but in reality this effect would have been small in most cases since entry for initial measurement was quick and did not allow for any significant ventilation dilution.
Additionally, the differences in real-time and sorbent tube results would be due to the limitations of real-time devices such as interferences between compounds and the limited range of VOCs the field devices can actually detect.
In summary, the field measurements indicated the presence and location of the major emission sources and a single overall level of major TVOC emissions whilst the laboratory measurements confirmed this for human exposure risk assessment and source apportionment of individual compounds that in most cases have widely varying toxicities. Both results are needed for risk assessment.
4.1.1 Thermal Comfort
Thermal comfort measurements were variable between the containers. This may be because the air-conditioners are adjusted by the individual occupants of the containers to suit their personal preference. In general it was observed that the fitted split system air-conditioners were capable of maintaining thermal comfort within the range described by ASHRAE 55.
4.1.2 Air Quality
Active (pumped air) adsorption onto carbon, DPNH-treated silica, Treated XAD-2 and XAD7 tubes that were analysed via GC, GCMS and HPLC are summarised on Charts 1–7 and presented in entirety in the file named; CV080411 FACSIA IAQ Results Spreadsheet V3.1.xls.
The conditions of containers prior to the 2-3 hour testing period varied from unopened and unused since fit-out and doors opened and air-conditioning on.
Six (6) of the twenty-three (23) Kitchen containers were tested with two (2) found to be un-occupiable, based on sorbent TVOC and formaldehyde data. All kitchens were not tested due to limited time and equipment resources. It was decided at an early stage in the trial to prioritise bedroom and office containers due to initial real-time data and odour assessments for kitchens being considerably lower.
Indoor air VOC concentrations ranged from 131,691 micrograms/m3 to less than 10 micrograms/m3, with a mean value of 15,837.2 micrograms/m3 as shown in Chart 8.
Indoor air formaldehyde concentrations ranged from 4362 micrograms/m3 to less than 10 micrograms/m3, with a mean value of 906.5 micrograms/m3 as shown in Chart 8 in ascending formaldehyde order.
Chart 8: FaHCSIA installed container accommodation TVOC and formaldehyde graphed in ascending formaldehyde order.
VOC and formaldehyde results were not significantly dependent on container temperature and humidity during testing, as shown in charts 9 and 10, indicating that release of contaminants is controlled by diffusion and not by evaporation.
Container age and prior venting and usage history data were not reliable and hence not taken into account at this stage.
Chemical pollutants (VOC and Formaldehyde) measured were found to be higher than guideline limits in many containers
CO2 and VOCs build up rapidly within the accommodation shortly after closing the doors.
Chart 9: FaHCSIA installed container accommodation TVOC and formaldehyde by temperature
Chart 10: FaHCSIA installed container accommodation TVOC and formaldehyde by humidity
5 Additional Observations
Investigations were made into possible TVOC and formaldehyde emissions in a selection of containers with markedly elevated field measurements were taken under bed mattresses, inside plastic wrapping of new mattresses and pillows, wall insulation in wall cavity, under floor vinyl, in bathrooms and inside cupboards in an attempt to isolate the source of emissions.
Findings can be summarised as follows:
Table 5: Ranges of TVOC measured by field instrumentation
| Location | Range TVOC (micrograms/m3) |
|---|---|
| Under bed mattresses | 140 – 7,200 |
| Inside plastic wrapping of new mattresses | 1,100 – 38,000 |
| Wall insulation in wall cavity | 3,100 – 70,100 |
| Under floor vinyl | 600 |
| Bathrooms | 0 – 8,000 |
| Inside cupboards | 0 – 3,800 |
| Inside plastic-wrapped pillows and doonas | 400 – 2,600 |
Figures 5 & 6: TVOC field measurement taken from hole in wall cavity to identify insulation emissions.
Chart 1: Formaldehyde Levels (micrograms/m3) in the GMB/CEB occupied containers.
Chart 2: TVOC levels (micrograms/m3) in GBM/CEB occupied containers.
Chart 2a: TVOC levels (micrograms/m3) in GBM/CEB occupied containers (reduced scale -values over 2,500 micrograms/m3 not shown).
Chart 3: Formaldehyde Levels (micrograms/m3) in Unoccupied Containers
Chart 4: TVOC levels (micrograms/m3) in Unoccupied Containers
Chart 5: TVOC levels (micrograms/m3) in NT Police Containers
Chart 6: TVOC levels (micrograms/m3) in Safe House Containers
Chart 7: TVOC levels (micrograms/m3) in Demountables
6 Conclusions and Recommendations
In view of the stated results and findings, the following conclusions can be made, based on health limits for TVOC and formaldehyde used in this report by CETEC following consultation with NICNAS. The other parameters are based on Cetec’s assessment:
- Overall, 86% of FaHCSIA containers are over the EA and NICNAS/NHMRC formaldehyde Threshold values and 3% are between the NHMRC and EA limits. Since only 3% are between NHMRC and EA limits, 89% of containers should not be occupied for any timeframe until verified remediation has occurred. Occupation is acceptable for 11% of FaHCSIA containers.
Percentage of Containers in Specified Concentration Ranges for TVOC and Formaldehyde (micrograms/m3)
| TVOC ≥1000 or Formaldehyde ≥100 (86%) | TVOC 500-999 and Formaldehyde <100 (3%) | TVOC <500 and Formaldehyde <100 (11%) |
| 163 containers | 6 containers | 20 containers |
In detail, the TVOC distribution for containers shows that 71% are unoccupiable, 9% manageable by occupant and 20% occupiable without management or remediation, as shown below.
Percentage of Containers in Specified Concentration Ranges for TVOC (micrograms/m3)
| TVOC <500 (20%) | TVOC 500-999 (9%) | TVOC >1000 (71%) |
| 38 containers | 17 containers | 134 containers |
The formaldehyde distribution for containers indicates that 80% are unoccupiable and 20% are occupiable without remediation as shown below.
Percentage of Containers in Specified Concentration Ranges for Formaldehyde (micrograms/m3)
| Formaldehyde <100 (20%) | Formaldehyde ≥100 (80%) |
| 37 containers | 152 containers |
- Tendency for CO2 and VOC to build up rapidly within the accommodation indicates a need for increased ventilation. However the exact design and configuration will need to be determined through research and trials on selected accommodation containers, according to the supplied Cetec proposal.
- The seventeen (17) un-tested Kitchen containers should either be classified as un-occupiable and remediated or tested to confirm contaminate levels, as 2 out of 6 tested were found to be above acceptable VOC or formaldehyde limits.
- Exact effective remediation options would have to be established through research and trials on test containers however, we would anticipate remediation of containers to include (but not limited to) the installation of either active or passive ventilation, ventillation of products responsible for emissions, air-conditioner modifications, air-conditioner filtration and/or removal of products contributing to emissions.
- Ventilation must account for the emission rate of VOC from internal materials, as materials will continue to emit at a rate that can contribute to above-limit ambient VOC levels close to emitting material, even if ventilation is improved. Consequently, occupants close to emitting materials, such as walls, bedding or desks, may still be exposed to above-limit VOC levels if ventilation is not configured and modeled correctly.
- Variability of VOC and formaldehyde results highlight the requirement for investigation into the conditions causing the variation.
- VOC and formaldehyde results were not significantly dependent on container temperature and humidity during testing indicating that release of contaminants is controlled by diffusion and hence remediation cannot be by surface chemical or heating treatments.
Cetec would be pleased to discuss any aspects of this draft for comment report with appropriate stakeholders.
| Dr. Vyt Garnys PhD, BSc(Hons) AIMM, ARACI, ISIAQ, ACA, AIRAH, FMA Managing Director and Principal Consultant |
Dr Robert Schiller PhD, BSc(Hons) NACE, IMEA Senior Consultant |
Adam Garnys BSc(Hons) Senior Consultant |
Disclaimer and Copyright
Disclaimer
CETEC has taken all reasonable care to ensure that the information contained in this report is accurate. The report is based on data and information collected by CETEC personnel during location visits and information accepted in good faith from various personnel associated with this work. However, no warranty or representation can be given that the information and materials contained in it are complete or free from errors or inaccuracies.
CETEC accepts no responsibility for any deficiency, misstatements or inaccuracies contained in this report as a result of omissions, misinterpretation or fraudulent acts of the persons interviewed or contacted.
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Users may view, print and download the contents for personal use only and the contents must not be used for any commercial purposes, without the express permission of FAHCSIA and CETEC. Furthermore, the material in this report, or any part of it, is not to be incorporated or distributed in any work or in any publication in any form without the permission of the FAHCSIA and CETEC.