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Sars and Negative Pressure Rooms

Background

The Severe Acute Respiratory Syndrome (SARS) outbreak originated in China, and has since spread to other countries including Canada, Hong Kong, Taiwan, Vietnam and Singapore. Cases of SARS are generally traced to recent travel in SARS affected countries or close contact with a SARS patient.

People affected by SARS develop a fever higher than 38°C, followed by respiratory symptoms, such as a cough, shortness of breath or difficulty breathing. In some cases, the symptoms become increasingly severe, and patients may require oxygen support and mechanical help to breathe. Other symptoms of SARS include muscle aches, headaches, and a sore throat.

Negative Pressure Rooms

When a person is infected with SARS, it is a health issue for everyone around them. A negative pressure room is designed to have an airflow direction from outside the room to inside, so that any viruses or bacteria are contained. This may be achieved by having a larger amount of air being exhausted from the room than is being supplied. The exhaust air has to be assumed to be contaminated, even if the patient is only a suspected SARS case, so all air leaving the room must be HEPA filtered, which is 99.99% efficient at the most penetrable particle size. Any health care workers entering the room must wear appropriate gowns and masks that can be removed and left in the room for disposal.

Almost any room can be temporarily modified to act as a negative pressure room with the use of a Negative Air Machine which contains a fan, pre-filters (to protect the HEPA filter) and a HEPA filter.

Airlab Ltd has successfully set up two temporary negative pressure rooms at an Auckland Hospital in response to the SARS virus. Other negative pressure isolation rooms have been operating for a few years that were set-up as TB rooms, but can also be used for SARS patients.

If you would like to know more about re-engineering an existing space and systems to create a negative pressure room, or hiring a Negative Air Machine, Please Contact Airlab Ltd on 0-9-262 1409.

What is Stachybotrys' Back to top

Stachybotrys contaimination on a wallStachybotrys exists as different strains (S. atra, S. chartarum and S. aternans). It is a saprophytic greenish-black fungus found worldwide that colonises particularly well in high cellulose material, such as hay, straw, paper and cellulose containing building material.

Stachybotrys is a slow growing fungus on media and does not compete well with other rapidly growing fungi. It grows and sporulates in low nitrogen materials at a temperature of 0-40°C and humidities above 55%.

Stachybotrys is capable of producing several toxins including tricothesene mycotoxin and Satratoxin H-, which is poisonous by inhalation.Individuals with chronic exposure to the toxin produced by this fungus report flu symptoms, general malaise, sore throats, diarrhoea, fatigue, intermittent hair loss, dermatitis and headaches. The toxins produced by this fungus are able to suppress the immune system affecting the lymphoid tissue and bone marrow.

This organism is very rarely found in outdoor air samples. It is usually difficult to find in indoor air samples unless it has been physically disturbed. The spores are in a gelatinous mass and will die readily after release. The dead spores are still allergenic and toxigenic. Absorption through the human epidermis has caused mild symptoms.

How do we detect the possibility of Stachybotrys contamination'

Usually the presence of visible fungi, evidence of water damage, and symptoms consistent with an allergic or toxic response to Stachybotrys.

Air monitoring should not be used as an alternative as it may give negative readings.

How should Stachybotrys be removed if it is discovered'

On a medium to large scale, qualified experts should only perform Stachybotrys abatements. Abatements generally involve total isolation of the infected areas from the remainder of the building, placing the area under negative pressure, minimising the production and spread of dust (which may contain spores) appropriate containment and disposal with double bagging of material.Areas should be sprayed with PVA glue to isolate visible spores before disposal in conjunction with full protective clothing and breathing apparatus.

If you would like to investigate a fungi related contamination problem in your building, Contact Airlab Ltd on 0-9-262 1409.

Airborne Particulate Back to top

Airborne particulate or dust can be separated into two categories:

  1. Inspirable dust; the portion of airborne dust that is taken through the mouth and nose during breathing and;
  2. Respirable dust; corresponds to the fraction of invisible dust <10 microns in diameter that is able to penetrate and deposit in the lower bronchioles and alveolar region.

Sources of airborne particulate include particles generated from building materials (fibreglass, fibres, cellulose fibres, asbestos fibres), combustion devices (gas appliances, gas hot water heaters and boilers), occupant activities (tobacco smoke, re-suspended dust), infiltration from outdoor sources (atmospheric dust and automobiles) and photocopy dust.

The monitoring of airborne particulate generally represents a harmless background of suspended dust and fibres, however they can cause serious health concern including irritation to the eyes, skin, respiratory passages and other soft tissue. The current process is to assess the airborne particulate by gravimetric assessment. The assessment can provide results as the respirable and inspirable fraction. The respirable fraction are those particles less than10 microns that penetrate and deposit in the lower bronchioles and alveolar region whereas the inspirable fraction is the portion of airborne dust that is taken in through the mouth and nose during breathing.

There are currently no standards or guidelines that pertain to the amount of airborne dust in the indoor environment except an indication to use the USEPA outdoor guidelines as stated in NZS 4303:1990 . Many IAQ investigations in New Zealand follow this approach and suggest using active sampling to AS 3640-1989 and achieving results less than 75 micrograms per cubic metre for an 8-hour exposure in indoor air in a non-industrial environment.

There seems little logic in this process since research in the last decade has focused on the respirable fraction because it is this fraction that produces the adverse effects apart from minor irritation to eyes and skin. The gravimetric determination of inspirable dust however maybe helpful in benchmarking a particular indoor environment. This will help validate whether future upgrades in filtration or changes in work practices within the space have lessened the extent of particulate loading. A particle counter may also be used to validate filter performance.

If you feel the level of airborne particulate is having an adverse affect to your health contact Airlab; we offer a workplace and personnel sampling service with professional advice regarding health and safety in the workplace.

Contact our Environmental Scientist : Deborah Shortt for more information.

Decontamination of Safety Cabinets Back to top

The internal plenums (spaces) of biological safety cabinets often become contaminated by aerosols of hazardous materials, which have been handled by the lab operators in the cabinet. During the testing and certification of Class I and II safety cabinets these plenums may need to be accessed from time to time. The decontamination by way of formaldehyde gas is the most common and reliable method for rendering microbiological contamination innocuous and thus minimising the risk of personnel exposure to hazardous organisms.

Decontamination is usually carried out prior to testing and/or maintenance, prior to relocation and when assurance of sterility in the cabinet is required.

Personnel that perform decontamination's should be trained in the procedures particularly with respect to the individual circumstances of use and have access to assistance in the event of difficulty; further they should have available protective equipment, such as a full mask respirator which will protect the eyes and the respiratory tract.

A means of measuring the amount of formaldehyde gas is recommended to detect leaks in the seals applied to the workzone and exhaust. Warning notices should be posted at doorways to prevent unprotected personnel walking into a potentially contaminated environment.

If you intend to have a Class I or Class II safety cabinet tested, repositioned or need assurance of sterility we recommend that it undergo decontamination. Airlab Ltd are experienced in the decontamination process, please contact our Controlled Environments Testing Manager for more information.

IANZ Testing LaboratoryBack to top

Surveys of the cause of laboratory acquired infections have shown, that only about 20% of cases followed known accidents with infectious materials; for example a spillage or from a needle stick injury. Many of the remaining 80% of these infections were believed to be due to exposure to aerosols of the kind that may be produced from common laboratory operations. Special containment equipment has been designed to protect laboratory workers where there is a risk from exposure to these aerosols.

One of the most widely used pieces of equipment is the biological safety cabinet, the principal device for the containment of aerosols generated in microbiological procedures. In conjunction with IANZ accredited testing of HEPA filter integrity, Airlab Ltd also offer a testing and validation service using Australian Standard test methods on a range of equipment.

Testing and validation is required annually on all laminar flow workstations, safety cabinets, cleanrooms and operating theatres. Decontamination is required before testing all Class II and cytotoxic cabinets. Airlab Ltd provide a professional and competitive service to all industries. For more information please contact our Controlled Environments Testing Manager.

Indoor air quality discussion group Back to top

Most people spend 90% of their time indoors, so clean, healthy air is important. Awareness of indoor air quality issues in New Zealand is gradually coming to the fore. In Auckland, New Zealand's largest city, a multi-disciplinary group of people has been formed, each with a professional interest in various aspects of IAQ. Currently we meet every three months on an informal basis, discuss current issues, share information and experiences.

If you would like to become part of this discussion group or would like to be included in the mail out of the minutes please contact us at New Zealand IAQ Discussion Group.

Lost Productivity Back to top

The indoor environmental quality of the modern workplace in recent years has experienced a heightened state of awareness among building owners, employers, building occupants, building managers and regulatory authorities. Because the average person can spend up to 95% of their time indoors, emphasis has been, generally overtime has been to have higher expectations of their work environment including its atmospheric conditions.

Two of the primary factors that are required for a suitable indoor environment are temperature and relative humidity. Generally termed as thermal comfort they combine with other factors such as ventilation efficiency and the absence of microbial and organic compounds.

Poor IAQ can have a significant negative effect on the employee's health and productivity. Productivity losses are an easily measured component. They can be evaluated by the poor quality and quantity of work accomplished by the employees.

Research supports a correlation between environmental comfort and worker productivity. Over the past fifteen years, dozens of scientific studies of productivity in the workplace prove that individuals respond very differently to their environments. Dissatisfaction with indoor environmental conditions has been routinely documented in studies conducted in both North America and Europe.

Many managers have already recognised that increased environmental satisfaction helps improve employee productivity. When environmental factors are carefully designed and controlled to meet the needs of employee, studies have reported productivity gains in the range of 15% for managerial employees and 17% for clerical employees. According to data obtained through research, a 2.8% productivity gain is possible in an open-office setting when employees are given control over their environments.

It therefore makes economic sense to provide staff with a comfortable, productive, complaint free work area. No matter how much office space you have the costs associated with conducting an indoor air quality audit are a fraction of the lost productivity dollars. Regular audits will ensure any onset of problems are identified and remedied before they get out of hand and become a costly exercise.

With regulatory obligations and an awareness of the costs incurred by lost productivity and absenteeism many employers are turning to Airlab Ltd for specialist IAQ advice. If you would like to know more about this subject feel free to get in touch with one our representative

Contact our Environmental Scientist : Deborah Shortt for more information.

Sick Building Syndrome Back to top

The term 'Sick Building Syndrome' or SBS came to light in the 1970's when health care providers were faced with increasing numbers of people having headaches and allergic like reactions to unspecified stimuli. Some of the reactions included lethargy, fatigue, headaches, dizziness, nausea, irritation of mucous membrane, eye irritation and sensitivity to odour. The causes of occupant's complaints are multi-factorial and often elusive. The syndrome's effects are well recognised but not clinically defined and tend to be relieved once occupants leave the building. The problem can involve chemical, microbiological, physical and psychological mechanisms.

With the property boom of the 1970's there was an ever increasing amount of refitting, tenancy changes, company growth etc. even though the building and its ventilation system may have been designed around the functional requirements there are no guarantees that the same building in two years hasn't changed tenancies and occupancy levels and in the process created indoor air quality challenges through inadequate ventilation. In the mid 1900's, building ventilation standards called for approximately 15 cubic feet per minute (cfm) of outside air for each building occupant, primarily to dilute and remove body odours. As a result of the 1973 oil embargo, however, national energy conservation measures called for a dramatic reduction in the amount of outdoor air provided for ventilation to a mere 5 cfm per occupant. In many cases the reductions in outdoor air supply were found to be inadequate to maintain health and comfort of building occupants. Inadequate ventilation, which may also occur if the heating, ventilation and air conditioning (HVAC) systems do not effectively distribute air to people in the building, is thought to be an important factor in SBS. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) recently revised its ventilation standards to provide a minimum of 15 cfm of outdoor air per person (20 cfm per person in office spaces). Up to 60 cfm per person may be required in some spaces (such as smoking lounges) depending on the activities that normally occur in the space. Ventilation and carbon dioxide go hand in hand and CO 2 has long been used as a surrogate indoor air quality indicator. High concentrations of CO 2 are indicative of a poorly ventilated building and effects occupants by way of lethargy and drowsiness.

Most indoor air pollution comes from within the building. Chemical contaminants such as adhesives, carpeting, upholstery, manufactured wood products, copy machines, pesticides, and cleaning agents may emit volatile organic compounds known more simply as VOCs, including formaldehyde. Research has shown that some VOCs can cause chronic and acute health effects at high concentrations. Low to moderate levels of multiple VOCs may also produce acute reactions in some sensitised individuals. The emission rate of VOCs from most building materials and furnishings is generally highest in newly renovated or new buildings. As well as chemical contaminants from indoor environments, outdoor environments can also be a source of pollutants. Pollutants from car exhaust (carbon monoxide), plumbing vents, and building exhausts (bathrooms and kitchens) can enter the building via poorly located air intake grilles, windows and other openings.

Microbial organisms are ubiquitous and there variety in normal air is enormous; some exist as viable particulate, others as non-viable and include dead spores, toxins and sub micron particulate. HVAC systems and occupied spaces in buildings provide many sources for their growth. Human exposure to airborne microorganisms has been documented to cause a variety of health effects from serious diseases such as Legionnaires to allergic responses causing sore throats, coughs, bronchitis, hair loss and wheezing, as well as eye and skin irritations. Another important factor in assessing a buildings air quality are thermal comfort levels. This includes temperature and relative humidity; these vary quite dramatically from person to person and are dictated by two factors-environmental and psychological. Environmental factors include temperature, air movement, humidity and radiant heat. Psychological factors include age, sex, state of health, body weight and build and degree of physical activity. These factors are more difficult to control and measure as people respond differently to the same set of conditions.

The number of IAQ related complaints has increased in recent years with increased building tightness, the growing use of synthetic materials, and energy conservation measures to reduce the quantities of outside air to occupied spaces. This combined with the abundance of other internally generated pollutants has elevated IAQ to become a significant environmental issue. So we must ask the question, "why do we care about IAQ'" There are two main reasons. The first being that the degradation of the indoor air quality (IAQ) has been associated with health effects of a largely differing degree of severity, ranging from acute irritations to chronic pathologies and even cancer induction.

The second reason for concern is related to the costs associated with poor IAQ. These cost are a by-product of declining health among effected building occupants and are measured by declining productivity and increased absenteeism. The approach and attitude to indoor air quality in New Zealand has been hampered by a general lack of knowledge. Many New Zealand buildings could use improvements in the air quality of occupied space. The potential consumers need educating as to the benefits of good indoor air quality. The benefits are the returns via increased productivity as opposed to the cost incurred through poor IAQ.

The future of IAQ in New Zealand building will see improvements in the way building owners manage buildings with respect to indoor air quality. Property management companies are becoming increasingly aware of IAQ issues and all the benefits of providing acceptable IAQ to their tenants. Heightened expectations of building occupants relative to the indoor air environment are driving IAQ improvements also. Some property companies have taken it a step further to provide independent audits of building air quality including the maintenance, air distribution, HVAC system controls logic and indoor air pollutants. This particle approach is allowing for the prevention of IAQ issues before they arise. Further more, it has added benefit of creating a team approach where the building owner/manager, occupants, maintenance contractors and IAQ professionals work together to enhance the building air quality. It, at the end of the day, is all about quality procedures and open communication rather than reactive measures to resolve issues of a 'Sick Building.'