Proposed changes to NFPA 20-2019
The potential changes to the 2019 edition of NFPA 20 could have a great impact on fire protection systems for high-rise buildings.
- Explore the 2019 edition of NFPA 20: Standard for the Installation of Stationary Pumps for Fire Protection.
- Identify how the proposed changes to NFPA 20 will impact fire protection systems for high-rise buildings.
The committee has completed processing the public comments for the 2019 edition of NFPA 20: Standard for the Installation of Stationary Pumps for Fire Protection. Public requests challenging the actions taken by the NFPA committee, if any, will be addressed during the technical meeting at the June 2018 NFPA Convention, and then submitted to the NFPA Standards Council for final approval.
Fire pump accessibility (status: passed). A proposal was submitted to require fire pumps that are not directly accessible from the outside to be accessible through an enclosed passageway in a fire-resistant-rated corridor from an enclosed stairway or exterior exit. These enclosed passageway portions of the building must have a fire-resistance rating not less than the fire-resistance rating of the fire pump room.
Gravity feed systems—water tank refill in very tall buildings (status: passed). A proposal was submitted to clarify refill requirements for fire protection water-storage tanks in high-rise buildings. This includes permitting refilling from a primary water supply (tank) for a different vertical fire protection zone located above the refill valve (i.e., gravity refill) or from a reliable domestic riser that can meet the refill-rate requirements. Redundant refill capacity is required for each tank and tank compartment. Each refill connection must be made to a different riser; all refill connections for tanks supplying the same vertical zone must be interconnected. In addition, each tank must be provided with an overflow sized for the maximum refill rate with a single automatic refill valve operating fully open.
The language in the 2016 edition of NFPA 20 permits gravity feed systems, but does not fully account for gravity feed refill in “very tall buildings.” NFPA 20 has requirements for very tall buildings without specifically defining them. In general, a very tall building is one that is impractical to evacuate in the event of a fire and/or is beyond the pumping capacity of the fire department.
Changes to NFPA 20 that impact high-rise fire protection systems
Since NFPA 20 started requiring access to the fire pump room in an earlier edition, there has been confusion over building codes not permitting access to mechanical spaces from exit corridors. This attempts to clear up the confusion. The intent of the requirement is to provide the fire department access to the fire pump room in an emergency.
Automated inspection and testing (status: passed). A proposal was submitted to add provisions for automated inspection and testing. Devices, meters, and equipment used to monitor or perform automated inspection and testing procedures that are subjected to system pressure must be listed. Automated inspection and testing devices and equipment installed on the fire pump system must be tested to ensure the accuracy of the automated inspection and testing devices and equipment. Automated testing devices and equipment are required to produce the same action required by manual testing to test a device and must discharge water where required by this standard and NFPA 25. In case of a failure of a component or system to pass an automated inspection or test, the automated system must generate an audible trouble signal in accordance with NFPA 72. With proper design, this permits automated testing of waterflow switches in tall buildings.
The design of high-rise buildings should implement the highest level of automated testing available at the time of the design. This can reduce testing costs and increase reliability through automated reporting and by allowing an increased testing frequency with minimal cost impact.
NFPA 20, NFPA 14, and NFPA 13: Standard for the Installation of Sprinkler Systems permit gravity feed systems; however, the tank-refill requirements in the 2007, 2010, 2013, and 2016 editions of NFPA 20 did not adequately cover gravity-tank refill as a viable option. The changes made to tank-refill requirements were made in recognition that it is possible to design a very tall building with gravity-fed standpipes/sprinkler systems, except for the top zone in the building. Pumps are required to refill tanks, but refill redundancy can be provided by gravity refill from a tank located higher in the building.
Traditionally, standpipe/sprinkler systems in tall buildings have been designed with the fire pump(s), and water tank when required, located at or below the bottom of the standpipe zone. One advantage of this design approach is the fire pump and standpipe control valves will almost always be below the floor where a fire occurs, providing access to the fire pump and valves without exposure to the fire. One advantage of a gravity-fed system is the system will function without power and without fire pumps operating. Gravity-fed systems will generally require fewer fire pumps but may require more express risers and/or water-storage tanks.
Mechanical room levels in high-rise buildings are selected with multiple considerations and may not be optimal for standpipe/sprinkler system zoning. Designing fire protection systems in high-rise buildings requires evaluating pressure implications with multiple design options.
Very tall buildings are typically light-hazard occupancies where the standpipe demand is greater than the sprinkler system demand. The maximum required flow rate required by NFPA 14 is 1,000 gpm (500 gpm for the first standpipe riser and 250 gpm for the next two standpipe risers) for a fully sprinklered building, which must be maintained for 30 minutes. This requires 30,000 gal of water. NFPA 14 requires the water supply to provide 100-psi residual pressure at the topmost outlet. For a gravity-fed standpipe system to provide 100 psi at the top of the standpipe zone, the tank must be located a minimum of 231 ft above the top of the zone.
Understanding the NFPA code-proposal process
NFPA standards go through multiple processes before formal acceptance and publication. Each standard has a committee of volunteers, typically around 30 primary members with alternates, who are selected by NFPA and have the responsibility to maintain each standard. NFPA provides a liaison to track the committee activity. The standards are typically revised every 3 years. Each revision standard starts with a period when the public may submit proposed changes to the standard. NFPA provides an online tool for submitting proposals, but written proposals also are accepted. Written proposals should be submitted on NFPA forms that show the necessary information to include with the proposal. In general, the proposal must include actual wording for the proposed change as well as the rationale for the proposed change. Proposals submitted without proposed wording are likely to be rejected. NFPA compiles the proposals into a document for the committee that handles that standard. The committee then meets and acts on each proposal. In this Committee meeting, members are permitted to propose changes without formally submitting them as a public proposal. At the public proposal meeting, actions require a simple majority to pass.
Once the committee has acted on the proposals, the NFPA liaison compiles the committee actions on an NFPA website and notifies the committee members through an online tool that the actions are available for formal balloting. After the ballots are cast, the results of the ballots are provided to the committee members and each member has a final chance to modify their ballot. Actions that receive a two-thirds majority of the committee votes are confirmed. Actions that receive less than a two-thirds majority vote are converted to “Committee Inputs” and are permitted to be reconsidered or revised at the next committee meeting.
After the final committee ballots, the NFPA liaison compiles and opens the results for public comments. Comments can be written or submitted online and generally include wording in a format that can be included in the standard. New proposals cannot be made during this period, but comments related to an original proposal are permitted. The NFPA liaison compiles the comments and submits them to the committee. The committee then meets and acts on the comments. In this committee meeting, members are permitted to propose changes related to the original proposals without formally submitting them as a public comment. At the public-comment meeting, actions require a simple majority to pass.
Once the committee has acted on the proposals, the NFPA liaison compiles the committee actions on a website and notifies the committee members through an online tool that the actions are available for balloting. After the ballots are cast, the results of the ballots are provided to the committee members and each member has a final chance to modify their ballot. Actions that receive a two-thirds majority of the committee votes are confirmed. Actions that receive less than a two-thirds majority vote are rejected, but may be reconsidered during the next stage.
After this committee vote, the NFPA liaison compiles and opens the actions for public review. The public may then submit a Notice of Intent to Make a Motion (NITMAM) directly to NFPA about changes or rejected actions made by the committee during the public-comment meeting. If no NITMAMs are submitted, the revisions go to the NFPA Standards Council for final acceptance and issuance.
NITMAMs are addressed at an NFPA convention session that is set aside for this purpose. Any attendee that meets the minimum membership-duration requirement can vote during this session. If a NITMAM is validated by NFPA, the submitter is permitted to make the motion on the floor during this session. The motion is then debated and voted on by the session attendees. A simple majority is required to pass. If the motion passes, the action is then submitted to the standard committee members for a final ballot. If accepted by two-thirds of the standard members, the motion is accepted and all revisions—including the motion go to the NFPA Standards Council for final acceptance and issuance. If the action receives less than two-thirds of the votes from the standard members, both the motion and the committee action on the issue are voided and the language from the previous edition of the standard is retained. All other actions are then submitted to the NFPA Standards Council for final acceptance and issuance.
Gayle Pennel is a project director with JENSEN HUGHES, specializing in fire protection system design and water supplies. He is currently chairman of the NFPA 20 Committee and a member of the NFPA 25 Committee. He has designed multiple high-rise, exhibition, warehouse, retail, and factory fire protection systems. Alex Popov is a fire protection engineer with JENSEN HUGHES with prior experience in fire pump testing for certification.