Fitting the theme of this issue, a reader recently emailed me to ask if the rules have fundamentally changed when it comes to smoke detection in the residential space.
Come to think of it, the reader might have a point, as nowadays there is a little more of a “commercial feel” to the way we protect one- and two-family homes.
In the past, smoke detection for the home was strictly a warning system for when we are asleep – detectors were placed outside our bedrooms, and later, that protection concept was expanded to include additional detectors inside “sleeping areas,” since so many people sleep with closed bedroom doors. A smoke detector on each level – excluding crawl spaces and unfinished attics – one inside each sleeping room, and one outside each sleeping area (within 21 feet of the bedroom doors) provided pretty good coverage for most homes. A split level home could give the privacy of having an extra 30 feet of hallway by adding just six steps up to another level; and for our purposes, if there was no door between the two levels, the smoke detection on the upper level sufficed as the detection for the lower level as well.
Size Matters
The strategies outlined above really didn’t do anything for the homeowner with a sprawling single-floor plan; in fact, residential fire codes have been updated with an extra requirement for these larger homes that are similar to full commercial coverage. With the bedrooms on one end of the house and the garage and laundry rooms on the other, the distance between them can be a factor in delaying early detection.
The 2016 version of NFPA 72, rule 29.5.1.3, includes new requirements for one- and two-family homes that state if one floor is more than 1,000 square feet in size, then additional smoke detection is required to provide early detection to the rest of the house – which is helpful even if the occupants are not sleeping.
Your two choices are to either provide a framework so smoke does not have to travel more than 30 feet to reach a detector, or provide a detector for every 500 square feet of remaining floor space.
To some, this additional detection reflects more of what a commercial building would be required to have – in the past, we protected the bedrooms; now, we must protect the entire floor.
Below is the full outline of the updated 2016 NFPA 72 requirements. Notice that we still get sort of a split-level exception in the last rule, 29.5.1.3.2 – which allows the detector on the floor/level above to count as the protection for the floor or even floors below if it is in the 30-foot travel distance path.
29.5.1.1 Where required by other governing laws, codes, or standards for a specific type of occupancy, approved single and multiple-station smoke alarms shall be installed as follows:
(1) In all sleeping rooms and guest rooms (2) Outside of each separate dwelling unit sleeping area, within 21 ft. of any door to a sleeping room, with the distance measured along a path of travel
(3) On every level of a dwelling unit, including basements
(4) On every level of a residential board and care occupancy (small facility), including basements and excluding crawl spaces and unfinished attics
(5) In the living area(s) of a guest suite
(6) In the living area(s) of a residential board and care occupancy (small facility)
29.5.1.2 Where the area addressed in 29.5.1.1(2) is separated from the adjacent living areas by a door, a smoke alarm shall be installed in the area between the door and the sleeping rooms, and additional alarms shall be installed on the living area side of the door as specified by 29.5.1.1 and 29.5.1.3.
29.5.1.3 In addition to the requirements of 29.5.1.1(1) through
(3), where the interior floor area for a given level of a dwelling unit, excluding garage areas, is greater than 1000 ft2 smoke alarms shall be installed per 29.5.1.3.1 and 29.5.1.3.2.
29.5.1.3.1 All points on the ceiling shall have a smoke alarm within a distance of 30 ft. travel distance or shall have an equivalent of one smoke alarm per 500 ft2 of floor area. One smoke alarm per 500 ft2 is evaluated by dividing the total interior square footage of floor area per level by 500 ft2.
29.5.1.3.2 Where dwelling units include great rooms or vaulted/cathedral ceilings extending over multiple floors, smoke alarms located on the upper floor that are intended to protect the aforementioned area shall be permitted to be considered as part of the lower floor(s) protection scheme used to meet the requirements of 29.5.1.3.1.
How has the new rule impacted your residential smoke detection strategies or methods? What other rules are impacting your residential fire protection installations? Let me know via email!
Greg Kessinger has been SD&I’s fire alarm and codes expert and a regular contributor for more than 15 years. Email him your fire & life safety questions for potential inclusion in this column at [email protected].
