Some (engineering) thoughts on Cornwall Regional Hospital

BY HOWARD CHIN

Tuesday, February 28, 2017

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Based on anecdotal information in the media, it is apparent that Cornwall Regional Hospital’s air-conditioning system was wrecked by politically expedient cost-cutting. I consider that it might still be working to specification if engineers operated and maintained the system.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc (ASHRAE) publishes rules to which most air-conditioning systems have been designed, and is now going to be the standard referenced by the new Jamaican Building Code, as soon as the politicians eventually get around to enacting the Building Act — now about seven years after the building code documents were published as Jamaican standards — to make the codes enforceable. It seems that this was not a government priority.


Under ASHRAE rules, most of a hospital has to have at least an amount of fresh air introduced equal to two times the volume of the rooms per hour; with much higher introduced amounts of fresh air for operating, recovery and other special rooms.


There are many other specific requirements, such as that operating rooms should have an air pressure higher than the surrounding connected rooms, and that the entering air should flow downwards above the person being operated on and exit the room through opposing walls, so that germs from medical personnel are unlikely to contaminate the patient and germs from outside cannot enter the operating theatre. Other relevant rules, if implemented in the original design, would have helped, such as every chemical storage room should have its own exhaust fan.


To save energy, the cool air exhausted to the outside of the building should be passed through Energy Recovery Ventilators (ERVs), which cool the incoming fresh air to discharge locations where it cannot be sucked back into the AC system.


The central air-conditioning system that has been spoken of should have a number of filter systems on the air entering different areas, examples of the number of filters of the air entering a room has to pass through three (each of increasing efficiency) for operating rooms, two for patient-care areas, and one for non-critical rooms such as laundries, food preparation, etc.


Even the air exhausted from certain areas, such as where infectious or radioactive materials might be in the air, must be filtered to the highest level before it can be disposed of. Filters must be replaced regularly and disposed of safely; needless to say this not cheap.


I see reported in The Gleaner of February 28, 2017 that mini splits were used to replace the air-conditioning system on the first three floors. Mini splits only cool, minimally filter, and re-circulate the air in a room thereby allowing many contaminants to accumulate. This is most likely the primary cause of the health ill effects experienced by the hospital staff.


In order to even start to fulfil the ASHRAE ventilation requirements and make these areas at least liveable, ERVs which might not fulfil the filtering requirements could be installed to exhaust airborne contaminants while the formal design and new system installation is being done. If filtration and fresh air exchange to the required level could be achieved in the ERVs it would be ideal until installation of the new, and energy-efficient central air-conditioning system.


The common use of mini split air-conditioning units is a really bad idea for almost every situation because of the lack of fresh air introduction. It is even worse when used in rooms where there are a large number of occupants (eg hotels or meeting rooms where I have seen mini splits), or in places where there are items giving off fumes such as paints, car tyres, fibreboard, etc. The result is that you find that you get more and more "stuffy" with possibly other symptoms increasing towards the end of the day.


Air-conditioning system design for hospitals is not a job for "cobblers", and considering the upcoming (hopefully) Building Act to make the building code enforceable, it should be done to comply with the ASHRAE rules.





Howard Chin, PE, is a member of the Jamaica Institution of Engineers. Send comments to the Observer or hmc14@cwjamaica.com.



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