Why More Thought is Needed for Manual Fire Alarm Systems for Apartment Buildings

Even the simplest of fire alarm systems requires at least some design consideration.

What makes a fire alarm system?

Before analyzing the word manual - it’s good to consider what makes a fire alarm system…a fire alarm system. There’s a reason formal construction language uses expressions like fire detection & alarm systems, or for that matter intrusion detection & alarm systems. Detection is a separate operation. Alarm, when considered in the scope of code references, typically means notification. Whether that notification includes horns, sirens, speakers , strobes, paging, text messaging, or voice mail - the point is to tell somebody that something happened.

Generally speaking, a true fire alarm system needs to notify all occupants of the building or area in question of a fire condition. The method used for notification is usually audible, i.e. horns or speakers. To accommodate the hearing-impaired, or audibly-challenged, or just plain deaf - visual notification is used as well in key areas. This is what sets true fire alarm systems apart from the much smaller and simpler sprinkler monitoring systems where the key component is monitoring and notification is only token in nature. It means not just token notification - everybody in the building needs to know to leave immediately.

Apparently subtle changes in fire alarm notification can have profound results

One of the most significant changes in fire alarm notification took place in the 2010 edition of NFPA 72. Previously, the requirements for the particular tone used for audible notification were relatively minimal - only the pattern was specified (the temporal tone). But the 2010 edition introduced the low-frequency requirement for sleeping areas. For the scope of this discussion, what concerns us is the power requirements of the low-frequency appliances. Additionally, a nod should be given here to ANSI/UL 864 - the testing standard for fire alarm panels and devices.

The short version is between NFPA 72 2010 (and later versions), and ANSI/UL 864 9th edition (10th is on the way as of this writing), the power requirements for fire alarm systems have at least doubled. This means larger power supplies and more circuits. The fire alarm riser diagram might remain the same - panel, sprinkler switches, horns & horn/strobes, but the installed footprint is going to be significantly larger. That means the wall space required is at least twice what it used to be. It’s tempting to simply pass the burden of all the fire alarm system design to the fire alarm contractor, and indeed they will carry most of it, but there must be allowances made for the physical size of the system components.

How else does the fire alarm impact the building

As building & fire departments become more educated additional requirements become imposed at the local level in advance of model code changes. A key example - nearly all fire alarm equipment is rated to operate within a given temperature range, typically 0°-49°C or 32°-120°F. Depending on the locale, rooms that are not temperature controlled can pass outside of these ranges - here in Las Vegas, we can swing past both! Traditionally most fire alarm control units have been located in either the fire sprinkler riser room or the main electrical room. Both such rooms typically are protected against freezing temperatures - the riser room by dedicated heaters to protect the sprinkler pipes from freezing, and the electrical rooms simply by the heat coming from the switchgear. But neither of these types of rooms traditionally have air conditioning for cooling purposes. Now that building & fire departments are recognizing the listed temperature ratings of the installed equipment - new requirements for air conditioning are being imposed. Not only does this mean additional cost to the building simply to have an air conditioner installed - there are real space issues to be concerned with. Wall-mounted mini-split air conditioners may be an ideal solution - but the wall unit, the piping, the electrical connections - these all consume some precious wall space in a sprinkler riser room that’s never spacious to begin with.

Another consideration is duct detectors. While the apartments themselves typically have no need for duct detectors, common use areas such as leasing offices or fitness areas may have sizable air conditioning equipment. And unless other factors have already required an area smoke detection system to be installed doing so will add to the fire alarm system cost. Consideration must be given for the servicing of these detectors - which means potentially altering the placement of the air handlers. At first, it may seem that making a concession to future service technicians by altering the building is an unjustified expense. But duct detectors and air filters require regular maintenance. It’s not a question of if - it’s a question of when, and the when is usually predetermined - often every three to six months. Locating the air handlers and their duct detectors in a cramped attic 20 feet above a marble tile floor may seem reasonable on paper - after all, technicians get paid to climb over obstacles and into small holes, don’t they? It’s not until the building representative gets presented the first bill for such, and realizes that this will be a regular expense, that the full impact of such design decisions are realized.

Considerations for future designs

Quite simply, trying to cram 10lbs of fire alarm, fire sprinkler, electrical switchgear, air conditioning, telephone distribution, cable tv distribution, irrigation controls, and other vital but unattractive building systems into 5lbs worth of riser & electrical room just doesn’t work. Get some insight from specialty contractors (not just manufacturer reps - talk to people who install & service these things for a living). It may make a difference of as much as a few thousand dollars in increased construction costs - but those will be easily recovered in the first year between avoiding changes during construction do to proper prior planning and reduced maintenance costs.

Realistic allowances for building systems result in accurate cost estimates and long-term savings. To reap the benefits of having AMFES design and install your system, contact us today!

Last updated: Sat 24 September 2022