Fire Alarm 411: A Fire Alarm System Installation, Part 1

This article originally appeared in the January 2025 issue of Security Business magazine. Don’t forget to mention Security Business magazine on LinkedIn and @SecBusinessMag on Twitter if you share it.

The fire alarm industry is full of rules. I’ve previously explained each of the six categories of rules, which apply, respectively, to manufacturers, what to install, how to install, to individuals, to companies, and as specified by contract. With the foundational rules now in place, let’s bring them all together and show how they work in real life.

Imagine the construction of a new mixed-use building in the city of Plano, Texas, with the following floors and floor heights (including slabs between floors):

• 1st floor: a bank, restaurants, and shops - 20 ft (6 m)
• 2nd floor: offices - 13 ft (4 m)
• 3rd floor: offices - 13 ft (4 m)
• 4th floor: residential condos - 13 ft (4 m)
• 5th floor: hotel - 13 ft (4 m)

The building has a footprint of 40,000 sq. ft (3,700 sq. m), totaling 200,000 sq. ft (18,600 sq. m). All exits discharge on the first floor. Let’s say that the contract is for a code-minimum system with design responsibility delegated to the fire alarm subcontractor.

Which Codes and Requirements Apply?

Start with the easy stuff. Plano is in Collin County, in the State of Texas, in the United States of America. The U.S. does not have a national fire code, so no federal requirements apply to the design and installation of this fire alarm system.

Texas legislation requires fire alarm system designers and technicians to be licensed and for companies to be registered. There are further requirements for insurance and documentation.

Texas is a home-rule state, thus, counties and cities adopt their own fire codes. Collin County has a fire code, but their rules only apply to unincorporated areas. This building is inside city limits, so we can ignore the county fire code.

On March 28, 2022, the Plano City Council passed an ordinance updating the city’s fire code from the 2018 edition of the International Fire Code (IFC) to the 2021 edition, with amendments. Cities often amend the model fire codes they adopt and, frustrating as it may be for contractors, not all cities adopt the same amendments. These amendments are crucial.

The IFC’s fire alarm requirements for new buildings are in Section 907, which is organized by building occupancy groups. Occupancy groups aren’t specified in the fire code directly – they come from the International Building Code (IBC).

According to Chapter 3 of the IBC, the following occupancy classifications apply to this example – Restaurants: Group A-2 (Assembly, food/drink consumption); Offices: Group B (Business); Shops: Group M (Mercantile); Hotel: Group R-1 (Residential, transient); and condos: Group R-2 (Residential, non-transient).

Using the Codes to Mandate Technology

Returning to IFC Section 907, we see that 907.2.1 addresses assembly occupancies, stating that a manual fire alarm system is required if the Group A portion of the building exceeds 300 people or 100 people on floors 2-5 (in our example).

A manual fire alarm system consists of notification appliances throughout, activated by manual pull stations at every exit stairwell and door. Section 907.2.1 then lets us omit the manual pull stations if the building has an automatic sprinkler system throughout and the fire alarm notification appliances activate when there is a water flow alarm.

We could look at the drawings to see if there will be a sprinkler system, but we don’t need to. Section 903.2 mandates automatic sprinklers for this case. Furthermore, 903.4 requires sprinkler systems to activate the fire alarm system notification appliances, if there are any.

Since we know that the facility will need fire sprinklers, we can leave out the pull stations (most of them – I’ll come back to this in a future column). The assembly occupancy requires notification appliances and monitoring of the sprinkler system.

The code for Group A occupancies also specifies that if the space is rated for more than 1,000 occupants, we must have a voice evacuation system, i.e., speakers instead of horns.

Determining the Occupancy Load

If you have a full set of drawings, depending on the design stage, you might have occupancy calculations already provided. If not, you can make an educated guess.

IBC Chapter 10, table 1004.5 shows occupant load factors for different types of occupancies. For the restaurant(s), we can use the entry for people seated at tables and chairs, which allocates 15 sq. ft (1.4 sq. m) per person. If we say that the seated assembly portion of the restaurants totals 7,000 sq. ft (650 sq. m), we can divide the occupant factor into the size of the space. That results in approximately 467 Group A occupants.

This is not an accurate method for calculating occupant load. For example, it ignores egress width and other requirements; however, the result will tend to be on the high side, which makes it useful for quick estimating. The calculated occupant load is below the 1,000-person threshold for voice evacuation in Group A occupancies, so this section of the code will not require speakers.

Look in the March issue for part two of this building installation, and feel free to reach out with questions!