Canadian Consulting Engineer

Hospitals: a Special Case

As fire alarm technology has developed, the systems in many existing hospitals have become outdated and obsolete. Many hospitals are moving forward with renovation projects that involve the complete removal of their existing fire alarm systems...

March 1, 2012   By By Phil Schuyler, P.Eng. H.H. Angus & Associates

As fire alarm technology has developed, the systems in many existing hospitals have become outdated and obsolete. Many hospitals are moving forward with renovation projects that involve the complete removal of their existing fire alarm systems and replacing them with modern addressable systems.

Recently our company has been commissioned to complete several hospital fire alarm renovation projects. Based on our experiences, here are some key design considerations that ensure a successful project.

Ensure the client has a firm understanding of the change in sound levels, from existing horns or bells, to speakers with digital tones.

Typically the alarm’s audibility will be significantly more with the new system in comparison to the old bell or horn style systems. This is always a point of contention, specifically regarding patient rooms as it is extremely difficult to reach the minimum 65dB without a speaker in the room. Yet with a speaker in the room the reading is typically well over 75dB. Considering the ambient sound level could be very low, the sudden change in sound during an alarm can cause hospital staff to be concerned for patient welfare. These issues must be brought to light early in the project so that the hospital administration and staff are aware of the change.

Understand the existing

ventilation system and the sequence of fan shutdowns.

This point is often overlooked as the fire alarm is typically designed by an electrical engineer, whereas the ventilation system generally comes under the purview of mechanical engineers.

If there are no accurate existing as-built drawings of the ventilation system, it would be worthwhile to engage a mechanical engineer to review the existing conditions. Although the building code applies typically to recirculation fans, it is our experience that some authorities prefer all the supply and return fans to shut down to avoid confusion. This is a request that should be reviewed with a mechanical engineer since supply fans to specific hospital functions such as operating rooms must remain active.

Existing required fire alarm boundaries need to be confirmed.

Over time, it is possible that the building’s fire alarm spatial boundaries were shifted but not updated to the fire alarm panel, software, or associated active or passive graphics.

It may be prudent to engage an architect who is knowledgeable about the building and its recent construction projects to review the boundaries. In addition, the required fire separations should be checked to ensure there are minimal penetrations. Since the nature of a renovation such as this is to make the building safer from a fire safety standpoint, the reviews should be included in the project scope. Our experience has taught us to estimate based on several spot checks and to carry a cash allowance to cover a unit cost for each penetration.

The building’s existing architectural features may not have caused issues for the original building

fire alarm system, but standards may have changed and all the

new installations must meet

the current standards.

Areas such as atriums, open ceilings, auditoriums, and beam and waffle pattern ceilings can pose challenges. The new systems must be carefully designed to ensure that these types of spaces still have adequate fire protection from both sprinkler and alarm points of view. It would be prudent to have specific references from CAN/ULC-S524 included in the design documents for these special case areas as the authorities may request additional clarification if there is concern.

Sprinkler and standpipe connections must be

reviewed and confirmed.

A site review with the hospital’s annual fire alarm inspecting agent will help to resolve this issue.

 Hospitals require special considerations due to

their type of occupancy.

It is critical to understand how the project is to be constructed in order to minimize any down time to the existing fire alarm system.

Time spent on construction in occupied patient areas needs to be carefully coordinated to ensure that all infection control procedures are met and also to allow the contractor time to ensure the system is installed properly.

It is also important to consider how the hospital fire plan accounts for evacuating the patients. The evacuation of seriously ill patients should be a last resort and fire alarm systems should be designed with this understanding.

Although the above is not an exhaustive list of all the design aspects that need to be considered when replacing a fire alarm system in an existing hospital, from our experience they are significant points that everyone involved in these projects needs to keep in mind.cce

Phil Schuyler, P.Eng., is an electrical engineer, project manager and fire and security design specialist with H.H. Angus & Associates, consulting engineers in Toronto.


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