HEALTH CARE: Burn Treatment Unit

Hemisphere Engineering

On the third floor of the Walter C. Mackenzie Health Sciences Centre in Edmonton is a new facility for treating those burned so severely they have to be kept for weeks in a moist, shrouded environment, shielded from any possible source of infection. The E. Garner King Intensive Care and Fire Fighters Burn Treatment Unit opened two years ago, making it only one of four such facilities in the world. There are two others in Boston, and one in Moscow.

Hemisphere Engineering were the consultants who designed the mechanical systems for the Edmonton project. Their component of the work was so significant it absorbed $3 million of the $8 million total construction cost.

The 2,500-m2 unit has 30 intensive care beds, and nine burn treatment beds. The entire facility had to be fitted with a new, independent Class I air-handling system in order to satisfy Alberta’s building code requirements that follow CSA standard Z317.2. The new system gives nine air changes per hour, using two identical air systems supplying 100% fresh air.

The air is filtered to 85% efficiency in most rooms, but in the isolation areas HEPA (high efficiency particulate arrestance) filters come into play. The air is exhausted and filtered in the interstitial space.

Special Bacteria Controlled Nursing Units were installed in two of the Burn Unit rooms to treat the worst victims. The units have a plastic enclosure around the patient’s bed, and within the shroud the air has to be kept hot and moist — as near as possible to body temperature, says Bob Campbell, P.Eng. chief mechanical engineer with Hemisphere. Separate miniature air handling units, custom-designed by Hemisphere, control the air supply into these plastic enclosures. The design was to maintain the environment at 80% relative humidity, and 30 centigrade. However, the patients found those conditions extremely uncomfortable, and Campbell reports that the doctors have recently agreed they can safely lower the relative humidity to 30% and still promote healing.

Infection control is vital for burn patients and the nurses tend to their needs from outside the plastic shroud, reaching inside only with their arms. After consulting with the doctors and nurses, Hemisphere has custom designed hand washing sinks that have highly polished stainless steel surfaces and ultra-violet ray devices to neutralize any microbial infections within the sink trap.

Another important aspect of the project was the provision of a heat recovery wheel on each of the air supply units. The cost was $75,000 for each one, but with the rising price of natural gas in Alberta during 2000-2001, the investment was paid back within one year. The supply fan configuration is “blow through” and the return fan is “draw through” to minimize the possibility of exhaust air carrying over into the supply stream. The engineers estimate that using the heat recovery wheel saves about the same energy as recirculating 60-70% of the air volume, and yet it allows the benefit of 100% outside air. It also makes it simpler to maintain the air pressure differentials that are so important in this medical unit.CCE

Client/owner: Capital Health Authority, University of Alberta Hospital

Mechanical & Electrical consultant: Hemisphere Engineering (R.A. Campbell, P.Eng., Vern V. Mantai, P. Eng.)

Prime consultant: Cohos Evamy Partners