Elevators and Fire Sprinkler Suppression - What you need to know
The requirements for elevator sprinkler protection are located in NFPA 13, Chapter 8, The Standard for the Installation of Fire Sprinkler Systems. Although as a designer for over three decades I would recommend not stopping there. There is often disagreement between the responsible design professional, fire protection contractor and the Elevator Inspector, so it is best to just have a conversation as different municipalities and agencies differ on the protection of elevators, the shaft, the elevator pit and the elevator equipment room Rule of thumb, a brief conversation with the State Elevator Inspector can save valuable time in rework at the end of the project when turning over and testing.
There are three main types of elevators commonly used with each having potentially different protection means and some commonalities:
- Traction (aka Electric and most common)
- Traction - Machine-Room-Less (MRL)
Traction Elevators use a counterweight to offset the weight of the cab and occupants. The traction elevator uses cables and pulleys with the counterweight to lift the cab with a gearless permanent magnet motor to power the cables or belts. They are used in buildings of all heights including high-rises. The cables or belts can be a combustible polyurethane coated or similar combustible material, so it is best to determine up front what is specified for the project. This becomes important to meeting code requirements for sprinkler suppression.
Hydraulic Elevators use the compression of hydraulic fluids to lift the cab and occupants with a piston that travels inside a cylinder powered by an electric motor. They are generally used in buildings less than 60 feet tall. The hydraulic fluid can be combustible and is also best to determine if a non-combustible hydraulic fluid is specified for the project.
- All concealed combustible elevator shafts shall have, at a minimum, one sprinkler at the top of the shaft, generally within 2 feet of the smoke or heat detection device.
- Concealed shafts of non-combustible or limited combustible and contents, with a suitably rated car enclosure, do not require sprinklers and additionally the elevator car meets, and is constructed in accordance with ASME A17.1 Safety Code for Elevators and Escalators. This safety code limits the combustibility within the elevator car.
- Traction elevators even in non-combustible or limited combustible shafts that have combustible cables or belts shall require one sprinkler at the top of the shaft, generally within 2 feet of the smoke or heat detection device.
- Sprinklers shall not be required in the elevator hoistway when the suspension means (cables/belts) provide not less than a FT-1 rating when tested to the vertical burn test requirements of UL 62, Flexible Cords and Cables, and UL 1581, Reference Standard for Electrical Wires, Cables, and Flexible Cords.
- Accessible elevator shafts even with non-combustible surfaces, shall have one sprinkler installed near the bottom where trash, material and debris can collect at the bottom in the elevator pit. Sidewall sprinklers shall be installed at the bottom of each elevator hoistway not more than 2 feet above the floor of the pit. These sprinklers are intended to protect against fires caused by debris from lack of regular housekeeping and residual combustible hydraulic fluids that collect at the bottom of the elevator shaft.
- The sprinkler required at the bottom of the elevator hoistway, shall not be required for enclosed, non-combustible elevator shafts that do not contain combustible hydraulic fluids, but be wise to the local elevator codes and specific requirements as one requirement does not cancel out the other, so it is best practice at Ahern to just include the sprinkler at the bottom of shaft or elevator pit due to the possibility of trash, material and debris collecting creating a potential fire risk.
- For existing elevators all the rules above apply, although retrofitting an existing elevator requires some research on existing conditions. If the car does not meet the requirements of ASME A17.1, Safety Code for Elevators and Escalators. The State Elevator Inspector may not allow a sprinkler system to be installed unless upgraded to that specific Safety Code.
Tip: Read the project specifications to determine elevator requirements on the project, and as noted in the beginning of this blog, have a brief conversation with the State Elevator Inspectors Office to save valuable time in rework at the end of the project when turning over and testing.
Contact Ahern today. We are a qualified and highly respected leader in the fire protection industry and we are ready to partner with you today to inspect and service your fire sprinkler, fire suppression and fire alarm systems.
References: NFPA 13 (2016 edition), Internet TKE Elevators, IBC 2009, Meyer Fire Blog