By Bill Dickinson (websites ) - , CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14815966
Generally when people walk into a building, they assume that the building will provide a reasonable degree of life safety. NFPA 101, along with other codes and standards, provide the road map to achieving the reasonable degree of life safety that is generally expected by the public. However, unless enforced, codes and standards do not have the ability to protect building occupants. The authority having jurisdiction (AHJ) plays a vital role in enforcement of the code for the entire lifetime of a building; during construction, occupancy, and rehabilitation.
The term AHJ can apply to many different people and groups. A single building may have multiple AHJs which can include federal, state, and local agencies such as a fire marshal, electrical inspector, or health department inspector. In addition to the public sector, an AHJ might also include an insurance company, listing agency, corporate safety officer, and even a property owner.
18.104.22.168 The AHJ shall determine whether the provisions of this Code are met.
The role of the AHJ is to determine if a building, building component, or design meet the provisions and intent of the code. This can be a challenging task as the code has a very broad application including new and existing buildings and structures that can range from an existing single-family home to a new high-rise hospital. Paired with rapidly changing technology, innovation, operational needs, and design trends, it is not feasible to have the code address every possible design scenario. As a result, often times an AHJ is required to use the code requirements and their professional judgement on whether a design is code-compliant or meets the intent of the code.
In addition to determining compliance with the prescription requirements, there are many provisions which are left to discretion of the AHJ. For example, a hazardous area is defined as an area in a building that poses a degree of hazard greater than the general occupancy. The ambiguity to this definition is intentional to give the AHJ the ability to determine on a case-by-case basis if an area should be classified and protected as a hazardous area. While a storage room larger than 100 sq. ft. storing combustible materials would be required to be classified as a hazardous area in a new health care occupancy, the same storage room in an assembly occupancy would only be required to be classified as a hazardous area where the quantity of combustible supplies is “deemed hazardous” by the AHJ.
6.4.5 Modification Requirements for Existing Buildings. Where it is evident that a reasonable degree of safety is provided, the requirements for existing buildings shall be permitted to be modified if their application would be impractical in the judgement of the authority having jurisdiction.
The code also provides the AHJ with a degree of flexibility when applying the provisions of the code to existing buildings where “a reasonable degree of safety is provided.” It is not the intent of this section to make the requirements of NFPA 101 not applicable to existing buildings, but there are many times in existing buildings where modifications to the building would require significant effort and expense for minimal life safety benefit. For example, an AHJ may permit an existing non-compliant travel distance in an existing building that has been retrofitted with sprinklers, if they determine that a reasonable degree of life safety is provided.
Ultimately, the determination if a building, new or existing, is safe for occupancy is up to the AHJ. As NFPA 101 (4.6.9) indicates, a building shall be occupied only where “no serious life safety hazard exists as judged by the authority having jurisdiction.” It is also important to remember that each potential AHJ may have different goals and thresholds that they consider an acceptable level of life safety. For example, your local fire marshal may have a different goal than your insurance company, and so when enforcing the same code may have varying thresholds of what they consider acceptable.
To uphold the level of life safety that the public expects, it is important during the entire lifetime of a building, to understand the role and responsibilities of the AHJ, and their enforcement of the code in the interest of building occupant safety.
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Did you know NFPA 101 is available to review online for free? Head over to www.nfpa.org/101 and click on “FREE ACCESS.”
Photo Courtesy of Andysmith248 [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
As a staff engineer I often get the question through our technical question service (TQS) if a smoke control system is required. Although there are a few times where NFPA 101 prescribes the use of a smoke control system, for the most part it is a choice by the building designer to comply with performance criteria in the .
Smoke control is an engineered system that is designed to modify the movement of smoke. Where the NFPA 101requires a smoke control system, it is required to comply with NFPA 92, . There are two main types of smoke control systems per NFPA 92: smoke containment systems and smoke management systems. The purpose of smoke containment system is contain smoke to a given area and prevent it from entering another area, such as with a stairwell pressurization system. The purpose smoke management system is maintain tenability of an area or means of egress and reduce migration of smoke between the fire area and adjacent spaces, such as with an atrium smoke control system.
There are several times in which NFPA 101 prescribes the use of smoke control:
There are other times that a smoke control system may be required in order to meet a performance criterion. Such as new atria which require an engineering analysis to demonstrate that the smoke layer interface is maintained above the highest opening or at least 6 ft. above the highest floor level for a time period of 1.5 times the calculated egress time or at least 20 minutes. An atrium may be able to achieve this performance criteria without the use of a smoke control system, however, for some buildings the installation of a smoke control system may be necessary to achieve a desired atrium design.
Stairwell pressurization systems as a means to provide a smokeproof enclosure is another common example of smoke control systems. Smokeproof enclosures are required to be designed to limit the movement of smoke, this is permitted to be achieved through natural ventilation, mechanical ventilation incorporating a vestibule, or by enclosure pressurization.
In addition to atria and smokeproof enclosures, smoke control systems may be utilized to meet a design criterion for buildings and designs including underground and limited access buildings, smoke-protected assembly seating, stages in assembly occupancies, detention and correctional occupancies, mall concourses, as part of an engineered life safety system, or in performance-based designs in accordance with Chapter 5.
For most buildings and designs, with the exception of underground buildings and mall concourses, the will not prescribe the use of a smoke control system. However, based on the use and design of the building, the use of a smoke control system may be desired or necessary to meet the prescribed performance criteria in the .