Your questions answered: Specifying fire and life safety systems

Engineers should be aware of the contents and intent of the building when specifying fire detection, notification and suppression systems.

By Toby White and Jonathan Sajdak November 1, 2022
Courtesy: Consulting-Specifying Engineer

Active and passive fire protection systems are specified to ensure the safety and well-being of building occupants in case of a fire or other incident. Protecting the occupants of the building from the effects of fire is the primary objective in the majority of cases.

During the Oct. 12, 2022, webcast entitled “Specifying fire and life safety systems,” the presenters ran out of time. Additional answers to questions are listed here.

Presented By:

  • Toby White, PE, LEED AP, Associate Principal, Fire and Life Safety, Arup, Boston
  • Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston

 

Can I use bells instead of horn in a hospice facility?

Jon Sajdak: Chimes are sometimes used in hospice facilities. However, the exact type of notification devices should be coordinated with the local authority having jurisdiction (AHJ) for approval.

Is there a square footage limit for manual fire alarm system?

Toby White: International Building Code bases the requirements for manual fire alarm on number of occupants and number of stories. Refer to IBC 907 section called “Where required.” It is not based on area.

Where do we find information on requirements for firewall and ceiling hour ratings?

Toby White: IBC Chapter 7 covers all fire resistance rated barriers, partitions, smoke barriers and smoke partitions with regard to ratings. Reference to required barriers can also be found elsewhere, such as in Chapter 4, 9 and 10.

Should the building’s smoke control system be directly controlled by the fire alarm system or the building/HVAC automation system?

Toby White: Should be the fire alarm system and smoke control panel. The building HVAC system (or building automation system) would need to be UUKL listed to serve this function and it is possible.

What is a mass notification system? Where defined?

Jon Sajdak: Mass notification systems are defined in NFPA 72: National Fire Alarm and Signaling Code. The standard in-building mass notification system is defined as:

“A system used to provide information and instructions to people in a building(s) or other space using intelligible voice communications and including visual signals, text, graphics, tactile or other communication methods.”

Which code mandates the use of mass notification systems?

Jon Sajdak: This depends on the jurisdiction and what codes are applicable to the project. For instance, Department of Defense projects require mass notification systems in 4-010-01. The IBC starting in 2018 requires a risk analysis to be performed for certain facilities. And the results of that analysis dictate whether the system is required.

Are there any language requirement for voice notification?

Jon Sajdak: Typically, the language is specified to be suitable for the intended occupant use. This may vary based on the location of the project and in some cases multiple languages may be used to help deliver messages.

How do we determine where the remote annunciator should be located (internal or exterior) locations?

Toby White: Most practical location of fire department response is a good first suggestion, but final placement is always subject to the fire department approval.

Courtesy: Consulting-Specifying Engineer

Can the backup power generator, for fire pump, use natural gas for a fuel source?

Toby White: NFPA 70: National Electrical Code does not prescriptively permit both power sources to be from a municipal utility source, unless proven to the AHJ that the source is reliable. This is subject to AHJ approval. Since primary power is normally from the utility electric, then utility gas would need to be proven to be reliable.

What is life expectancy for fire alarm systems?

Jon Sajdak: Most fire alarm systems can last 10 to 15 years before needing software or hardware updates. Routine maintenance and the conditions the fire alarm system is exposed to also play a role in the life expectancy.

Is there a preference for BAS or fire alarm doing the smoke control?

Toby White: Fire alarm with smoke control panel, unless the BAS is listed UUKL.

How about exhaust methods or pressurization methods for elevator shafts?

Toby White: Elevator shafts can be pressurized in lieu of elevator lobbies per IBC 909.21 (2015 edition) where permitted by other sections of the code.

In British Columbia, Canada, is a fire alarm strobe required in a high riser commercial building? Are there any cases in that the strobe could be exempt?

Jon Sajdak: I am not familiar with the Canadian building codes. I would recommend coordinating exemptions with the local AHJ.

Can you show some negative pressure in pressurization examples please?

Toby White: using the pressurization method of smoke control, the smoke zone must be bound by smoke barriers and opening protections with smoke and draft control assemblies. The IBC Section 909 stipulates maximum allowable leakage rates through smoke barrier construction. The smoke control system is designed to exhaust the compartment to achieve a minimum pressure differential across the barrier, normally measured at doors, of at least 0.05 inches w.c. Providing in depth examples of smoke control design was not considered in this session given the amount of content to cover in a short time.

How do we specify fire alarm system for industrial areas (both manned areas and areas which are not manned)?

Jon Sajdak: Typically, all areas need audible coverage from the fire alarm system. Visual coverage is provided in common use, occupied areas. Special consideration for weatherproof or explosion proof devices may be required in industrial areas. Special means of detection is also typically provided (air sampling smoke detection, UV/IR, etc.)

Which equipment should be on a generator for smoke control systems?

Toby White: All active components of the smoke control system shall be powered by standby power unless fail-safe occurs in the smoke control mode configuration.

For a large building with multiple floors, when a very localized fire occurs, will the sprinkler system range be automatically limited to prevent large area water damage?

Toby White: Only the sprinkler heads that reach activation temperature will operate. Many fires are controlled with one or two sprinklers only. Cooling of the fire by these sprinklers prevent additional sprinklers from reaching activation temperature.

Can a fire alarm control panel use only cellular dialer or is another dialing out medium required?

Jon Sajdak: There are multiple means to supervise/monitor the fire alarm panel. They can be physically be connected to a network via fiber, telephone lines or be constantly attended to.

Can a building occupancy change within the same building? Example: An office building that has a small medical clinic or facility in it?

Toby White: Yes, this is considered a “mixed-use occupancy.” Many buildings have multiple uses. The building code (IBC Chapter 508, for example) gives direction on whether these different uses need fire rated separation between them or not.

Are windows sprinklers cheaper than 2-hour rated glass?

Toby White: Usually yes, since the building already has a sprinkler system and these are simply specialized heads.

How is DAS enforced? Can it be accepted as official substitute of fire phones by regulations?

Jon Sajdak: Each jurisdiction has different radio coverage and the criteria is laid out in the International Fire Code and NFPA 1221: Standard for the Installation, Maintenance and Use of Emergency Services Communications Systems for what levels of coverage is required in a building. Most times, it is actually a preference to use a DAS system in lieu of fire fighter phones.

Can you speak more on pathway survivability? When it is required? And what does that look like?

Jon Sajdak: Pathway survivability is required where partial evacuation or relocation Is used. Fire alarm panels and circuits need to be protected with 2-hour enclosures or circuits. Additional information can be found in NFPA 72.

On slide 33, one performance criterion for atrium smoke control is to maintain the smoke layer greater than 6 feet above the highest occupied surface. I think you said that would be the fourth floor. Why not the top floor? Is this, the highest floor, something that is determined during the rational analysis?

Toby White: For limited occupied high-level spaces, such as walkways along the atrium, you are permitted to allow the smoke layer to descend below that as long as safe egress from those levels can be achieved before the smoke layer overtakes the levels. In our example, we chose the fourth floor as our “open” floor, which required extended tenability. Every project is different and must be thought through as part of the performance-based design.

Do the consultants ever recommend temporary systems for smoke detection, water detection and evacuation of the construction of the sites?

Jon Sajdak: Temporary detection is mostly used when renovations are ongoing, in which case heat detectors or smoke detectors are commonly used.

Why are some pull stations single action and some dual action? What are the advantages of both?

Jon Sajdak: The single action pull station is easiest to use and requires one motion to activate. The dual-action requires to separate actions. Certain occupancy types are better suited for double action pull stations. Owner design criteria or AHJs may require a certain type.

As hydrofluorocarbon clean agent systems are phasing out, while reviewing shop drawings is this something we should be paying extra attention to?

Jon Sajdak: Yes. With that being said, there are a lot of variables with designing clean agent systems. It’s important to coordinate the type with the local authority and make sure the room is designed and suitable for the clean agent used.

In California we are required to monitor the wiring and antenna of the ERRCS in some jurisdictions. Do you think this will become more prevalent in other states? Clarification. Are 2-way emergency responders communication enhancement systems (ERCES) required or is the emergency responders radio coverage (ERRC) required and the ERCES the solution to provide coverage if it is lacking?

Jon Sajdak: In most projects I have seen, the ERRCS has multiple monitor points including the ones you mentioned. Typically, we spatially plan for the system and then during construction test coverage to determine whether or not the system is required. Sometimes, the AHJ will direct you to either install one in the beginning or tell you their coverage in the jurisdiction is adequate already.

What could be the better approach to design a fire detection and suppression system for a standby generator in a walk-in outdoor enclosure? We had a lot of problem because some architects and AHJ treat an outdoor generator enclosure as “not a building.”

Jon Sajdak: Typically heat detectors are provided in these outdoor generator enclosures due to their exposure to exterior conditions. The AHJ has final say in whether the enclosure is classified as a building or if it needs sprinkler protection, but most times I do not see these being classified as buildings or part of a building area.

When do you provide fire alarm wiring in conduit?

Jon Sajdak: In most cases, conduit is provided in areas without finished walls or ceilings. J-hooks or cable trays can be used in above ceiling spaces. This is really an owner requirement/preference and not something dictated by NFPA 72.

Is there any situation where a kitchen hood exhaust fan should be shut down by the fire alarm system or should they be allowed to continue running to purge smoke?

Toby White: It depends! The fan should continue operation if the fire is under the hood. If the fire is outside the commercial kitchen, it could cease operation under alarm conditions, but it sometimes does not need to. It is not like an air handling unit or rooftop unit that may recirculate smoke into the building.

How should elevator controllers react to fire alarm system activation?

Toby White: Recall Phase I operation is required for lobby smoke detection. Some designers select to recall on additional detection. Fire service elevators must recall on any fire alarm activation.

 

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Page is a CFE Media content partner.


Author Bio: Toby White, PE, LEED AP, Associate Principal, Fire and Life Safety, Arup, Boston. Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston