Code Red Consultants
  •  

Insights Category: Technical Information

Previously in our Fire Walls, Part 1: What do they get me? post, we had outlined what fire walls do from a code perspective. In addition to what role these assemblies serve, questions commonly arise relative to the construction detailing of fire walls given the number of requirements to consider.

Structural Connection

The building code allows two options for fire wall construction:

  • The first option is a single fire wall assembly that is structurally independent from both buildings (NFPA 221, 6.3 & 6.4).
    • Cantilevered Fire Walls are entirely self-supported and nonbearing. No connections are permitted to building(s) or contents on either side other than to the flashing and should be constructed where there is a break in the structural framework (NFPA 221, 6.3).
    • Tied Fire Walls are centered on a single column line or constructed between a double column line. The structural framing on either side lines up horizontally and vertically, and supports the roof (NFPA 221, 6.4).
  • The second option is the construction of a double fire wall assembly consisting of two back-to-back fire walls. Each fire wall is supported laterally by the building frame on its respective side and independent of the fire wall and framing of the opposite side (NFPA 221, 6.5).

All fire walls are required to be designed and constructed to remain after collapse of the structure due to fire on either side of the wall (NFPA 221, 6.2.1). Specifically, these assemblies are required to be continuous both vertically and horizontally and have specific termination requirements.

Fire Resistance Rating

The required ratings of fire walls are based on the occupancy classifications within a building (IBC Table 706.4). Double wall assemblies are considered to have a combined assembly fire-resistance rating; for instance the equivalent of a 3-hour, single fire wall is 2, 2-hour rated fire walls in a double assembly (NFPA 221 Table 4.5).

Openings

The aggregate width of protected openings at any floor level in a fire wall is not permitted to exceed 25% of the length of the wall (780 CMR 706.8). Egress door openings within double fire walls are required to be protected with a pair of doors and a vestibule (NFPA 221, 5.8.4.2).

Whether a single or double fire wall is being explored as part of the design, it is important to review the necessary fire-resistant rating, structural stability, continuity, and opening requirements applicable to both options, as well as detailed criteria from 780 CMR Section 706 and NFPA 221.

Energy Storage Systems (ESS) are a source of available and reliable power that can provide flexibility to electrical grids during peak usage and assist with load management and power fluctuations. NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, addresses the installation of energy storage technologies and aims to mitigate the hazards related to these systems.

NFPA 855 contains size and separation requirements designed to prevent fire propagation from one ESS to adjacent combustible materials (other ESS, wall assemblies, exposures). These limitations specifically focus on indoor installations in non-dedicated buildings and outdoor installations less than 100 feet from exposures:

  • The maximum stored energy per unit is limited to 50 kWh
  • The separation distance between units and wall assemblies should be a minimum of 3 feet
  • The maximum stored energy of all the ESS units comprising the system is limited to a threshold value based on the battery technology

NFPA 855 also requires most new Energy Storage System (ESS) installations to be listed in accordance with UL 9540, Standard for Safety of Energy Storage Systems and Equipment. UL 9540 provides design, construction, and performance requirements for ESS.

Exceptions in both NFPA 855 and UL 9540 allow for ESS installation with increased stored energy and reduced separation distances. Approvals for larger ESS depend on the results of large-scale fire testing conducted in accordance with UL 9540A, Standard for Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems. UL 9540A provides critical information regarding the fire performance of ESS undergoing a thermal runaway event. Fire testing is conducted at the cell, module, and unit level to evaluate the potential for fire spread and toxic gas emissions from the ESS, as well as the performance of the mitigation solutions to limit the consequences of the thermal runaway event.

An extensive amount of data is produced from the UL 9540A testing. Correct interpretation of the results is essential for the AHJ to confidently evaluate the safety of an ESS installation.  We are here to help with the review of UL 9540A test reports and the interpretation of UL 9540A testing data. If you have questions related to ESS fire testing in accordance with UL 9540A, please contact us at info@crcfire.com.

Energy Storage Systems (ESS) are becoming a prevalent solution to anticipate and mitigate electrical grid disruptions for commercial, industrial, and residential applications.  ESS provide energy reserves to reduce power peaks and stabilize fluctuations in energy supply.  Various ESS technologies have been and are being developed.  Hazards related to ESS, such as fire and toxicity, cannot be ignored.

NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, was developed to provide the minimum requirements to ensure safe design, installation, and operation of ESS.  Depending on the technology, the amount of energy stored, the location, the design, or potential hazards in the vicinity of the ESS, a Hazard Mitigation Analysis (HMA) may be required by the AHJ.  The HMA is a systematic method that considers the various hazards related to the installation, identifies potential failure modes as well as their causes and effects, and develops appropriate mitigation solutions.

NFPA 855 requires the HMA to evaluate the consequences of:

  • Thermal runaway conditions
  • Failure of an energy storage management system
  • Failure of a required ventilation or exhaust system
  • Failure of a required smoke/fire detection system, fire suppression, or gas detection system

The AHJ can require the HMA to include additional failure modes.  It can be completed by either a design team or a third-party.  To be approved, the results of the analysis will need to demonstrate that the mitigation solutions of the installation provide proper fire containment, suitable explosion control, safe egress, and adequate toxic and flammable gas management.  If you have questions regarding how to develop an HMA or if you are in need of a third-party HMA review, please contact us at info@crcfire.com.

Energy Storage Systems (ESS) are starting to play a critical role in the development of microgrid systems, the integration of renewable energy, and by improving the utilization and efficiency of such hybrid systems.  They have rapidly gained popularity in commercial, industrial, and residential applications.  Different technologies are currently used to store energy:

  • Pumped hydro storage (hydroelectric power)
  • Capacitors
  • Compressed air energy storage
  • Flywheels
  • Batteries

ESS designs vary greatly depending on the technology used. Over the last few years, Lithium-ion (Li-ion) battery-powered ESS have attracted significant interest due to their high energy density, voltage performance, and long-life cycle.  Two common aspects among the different technologies are the need for an adequate understanding of the hazards involved and appropriate measures to ensure safety. NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, provides requirements for mitigating hazards related to the design, installation, operation, and maintenance of ESS, not only powered by Li-ion technology but also for any ESS that exceeds the energy capacity threshold listed in the standard.

ESS powered by solutions such as Lead-Acid Battery, Sodium Nickel Chloride Battery, Solid State Battery, Iron-air Battery, and Flow Batteries are also required to be designed, installed, and maintained in accordance with NFPA 855. Several of these technologies are new, and risk and mitigation analyses need to be conducted in order to appropriately evaluate the fire and toxic hazards related to these ESS.

Information related to the equipment, its installation, and testing data is paramount to determine the degree of safety offered by the ESS when subjected to different failure modes. Hazard Mitigation Analyses and NFPA 855 Compliance Reviews conducted by the design team, a third-party, or the AHJ offer comprehensive evaluations of the level of safety of ESS installations.

For projects in Massachusetts, multiple dwellings are required to comply with 521 CMR.  In multiple dwellings for rent (not for sale) that contain 20 or more units, at least 5% of the dwelling units must be Group 2A units (521 CMR 9.4).  521 CMR includes unique requirements that designers may not be familiar with based on experience with other requirements such as FHA or ANSI A117.1. Some of these high-level requirements are included below:

  • Bathrooms
    • Wheelchair turning space is required to be provided clear of the door swing.
    • The centerline of the toilet is required to be at least 42” from the farthest side wall or the closest edge of an adjacent fixture. A minimum of 42” clear is required to be provided from the front edge of the toilet.
    • Clear floor space at bathtubs is required to be 30” x 72”. At least 12” of the clear floor space length is required to extend beyond the drain end of the tub.
    • Shower curbs must not be higher than ½” and must be beveled.
    • Bathtub faucets and mixing valves are required to be centered horizontally on the long wall, exactly 28” above the floor. Shower mixing valves are required to be centered horizontally on the long wall, 38”- 48” above the shower floor.
  • Kitchens
    • A counter space at least 15” wide is required to be provided on one side of the sink, cooktop, and refrigerator.
    • Built-in microwave ovens and at least one conventional oven are required to be wall ovens with the floor of the oven exactly 30” above the floor.
    • If corner cabinets are provided in L-shaped or U-shaped kitchens, a built-in lazy susan must be capable of being provided.
    • At least one base cabinet is required to provide a drawer or drawers).
    • Refrigerators are required to be either a unit with two side-by-side doors or a freezer above refrigerator unit.

Note that there may be other accessibility requirements applicable to your project.

Storage of hazardous materials is defined by 780 CMR Massachusetts State Building Code as “the keeping, retention or leaving of hazardous materials in closed containers, tanks, cylinders, or similar vessels; or vessels supplying operations through closed connections to the vessel” (780 CMR Section 202). For buildings utilizing a control area approach to address the inclusion of hazardous materials, such storage of hazardous materials is limited to defined Maximum Allowable Quantities (MAQs) per control area, which are listed in Table 307.1(1) and Table 307.12(2) of 780 CMR.

For most chemical classifications, the quantity of each chemical is permitted to be increased by 100 percent if the building is fully sprinklered, and another 100 percent if the hazardous materials are provided in what is commonly referred to as “approved storage”.  In the context of MAQs for physical hazards, footnote e to 780 CMR Table 307.1(1) specifies that approved storage could include storage in “approved storage cabinets, day boxes, gas cabinets, gas rooms, exhausted enclosures, or listed safety cans.”  For health hazards, 780 CMR Table 307.1(2) permits only approved storage cabinets, gas cabinets or exhausted enclosures for these purposes.  As discussed below, day boxes and safety cans are used for specific physical hazards and therefore are not applicable to health hazards.

Each type of approved storage is required to meet specific requirements, as prescribed by 780 CMR and/or 527 CMR 1.00 Massachusetts Comprehensive Fire Safety Code.

Approved Hazardous Materials Storage Cabinets: Hazardous material storage cabinets used to store solid and liquid hazards materials and are required to meet 527 CMR 1.00 Section 60.5.1.18 which prescribes the following minimum requirements:

  • Metal, double-wall construction with a minimum thickness of 0.044 inches (18 gauge) and minimum 1.5 inches of airspace between the walls.
  • Cabinet joints are required to be riveted or welded and tightfitting.
  • Doors are required to be well-fitted, self-closing, and equipped with a 3-point latch.
  • Entirety of the interior of cabinets are to be treated, coated, or constructed of materials that are nonreactive with the hazardous materials stored.
  • A 2-inch liquid-tight sump is required in cabinets utilized to store liquids.
  • Cabinets are required to be marked in conspicuous lettering that reads “HAZARDOUS – KEEP FIRE AWAY”.
  • Incompatible materials are not permitted within the same storage cabinet.

Depending on the material(s) stored within the cabinets, additional material-specific requirements may also apply.  For example, storage cabinets utilized for flammable or combustible liquids are further regulated by NFPA 30 Flammable & Combustible Liquids Code and require the cabinet be labeled with “FLAMMABLE – KEEP FIRE AWAY.”

Day Box: A day box is a portable magazine designed to hold explosive materials constructed in accordance with the requirements for a Type 3 magazine as defined by 780 CMR Section 202.

Gas Cabinet: A gas cabinet is a fully enclosed, ventilated noncombustible enclosure used to provide an isolated environment for compressed gas cylinders in storage or use (780 CMR Section 202). Gas cabinets are required to meet 527 CMR 1.00 Section 63.2.17 which prescribes the following minimum requirements:

  • Metal, with a minimum thickness of 0.097 inches (12 gauge).
  • Doors are required to be self-closing.
  • Cabinets are required to have self-closing limited access ports or noncombustible windows to give access to equipment controls.
  • Entirety of the interior of gas cabinets are to be treated, coated, or constructed of materials that are compatible with the hazardous materials stored.
  • An exhaust ventilation system is required, designed to operate at a negative pressure relative to the surrounding area.
  • Incompatible materials are not permitted within the same gas cabinet.

Depending on the material(s) stored within the gas cabinets, additional material-specific requirements may also apply.  For example, gas cabinets utilized for toxic, highly toxic, or pyrophoric gases are required to be internally sprinklered.

Gas Room: A gas room is a separately ventilated, fully enclosed room in which only compressed gases and associated equipment and supplies are stored or used (780 CMR Section 202). Gas rooms are required to be designed to the following minimum requirements per 527 CMR 1.00 Section 63.2.4:

  • Gas rooms are required to be provided with an exhaust ventilation system designed to operate at negative pressure in relationship to the surrounding area.
  • A minimum 1-hour separation is required to adjacent areas.
  • Separation of incompatible materials within gas rooms is required.

Exhausted Enclosure: An exhausted enclosure is an appliance or piece of equipment that consists of a top, a back and two sides providing a means of local exhaust for capturing gases, fumes, vapors and mists. These enclosures may include laboratory hoods, exhaust fume hoods and similar appliances and equipment used to locally retain and exhaust the gases, fumes, vapors and mists that could be released. Rooms or areas provided with general ventilation, in themselves, are not exhausted enclosures (780 CMR Section 202).  Exhausted enclosures are required to be designed to the following minimum requirements per 527 CMR 1.00 Section 63.2.18:

  • Noncombustible construction
  • Exhausted enclosures are required to be provided with an exhaust ventilation system designed to operate at negative pressure in relationship to the surrounding area.
  • Sprinkler protection is required within exhausted enclosures.
  • Incompatible materials are not permitted to be stored or used within the same exhausted enclosure.

Depending on the material(s) stored within the exhausted enclosure, additional material-specific requirements may also apply.  For example, the ventilation system serving exhausted enclosures utilized for toxic, highly toxic, pyrophoric, unstable reactive (Class 3 or 4) or corrosive gases are also required to meet minimum face velocities.

It should be noted that the definition of exhausted enclosure in 780 CMR Section 202 identifies laboratory hoods as one type of permissible exhausted enclosure.  However, within laboratories subject to NFPA 45 Fire Protection for Laboratories Using Chemicals, the storage of chemicals in fume hoods is explicitly prohibited per NFPA 45 Section 8.3.4.7.  In such laboratories, MAQ increases are typically achieved by way of approved storage cabinets.

Listed Safety Can: Safety cans may be utilized for the storage of flammable or combustible materials.  Where they are used to increase the MAQs per control area, safety cans are required to be listed in accordance with UL 30 Metallic and Nonmetallic Safety Cans for Flammable and Combustible Liquids.  Safety cans are further required to meet the following requirements, per Section 3.3.244 of 527 CMR 1.00:

  • Maximum capacity of 5 gallons (limited by UL 30 listing which is more restrictive than Section 3.3.244).
  • Safety cans require a spring-closing lid and spot cover designed so that it will relieve internal pressure when subject to fire exposure.

 

 

Light rail train stations are a unique occupancy in the eyes of the building code, given their transient occupants, large fuel loads in the form of train cars, and necessary interface and connectivity to surrounding public elements.  The required protection features and allowable design characteristics are distinct from most other building types.

Of particular importance is the specific allowance in NFPA 130 Section 5.2.4 for allowable vertical openings and interconnection between floor levels, which helps to aid pedestrian movement between various parts of the station:

In recognition of the additional hazards present in light rail stations and the interconnection of floor levels, NFPA 130 contains additional fire rating requirements to ensure public safety.  Most notably, all non-public areas of train stations are required to be separated from the public portions of the train stations (NFPA 130 5.2.4.2):

These non-public spaces can include mechanical equipment rooms, electrical rooms, storage rooms, battery rooms, employee-only spaces, and more based on the station’s infrastructure requirements.

Fire Department Connections (FDCs) are provided on buildings with fire sprinkler systems and/or standpipe systems, to allow the responding fire department to supplement the system’s water supply by pumping additional water into the building using an engine company. The two most common connection types for FDCs are 2.5-inch with National Hose (NH) internal threaded (female) swivel fittings and Storz connections. The type of connection required on a system should be determined by the local fire department based on the type of connections they use and their standard operating procedures. The numbers and/or sizes of the connection are determined by the type of systems they serve.

For sprinkler only systems, which are usually found in one- to three-story buildings, NFPA 13 (2019) §16.12.3 requires the FDC serving that system to have two 2.5-inch connections unless the following requirements are met:

  1. Local fire department does not conform to NFPA 1963, then the AHJ shall designate the connections.
  2. The use of threadless couplings (Storz) shall be permitted where required by the AHJ and is listed for such use.
  3. A single 2.5-inch connection may be used where the system riser is 3 inches or less.

NFPA 13 does not require additional inlets based on the sprinkler system demand – only two inlets are required. The system designer has the option to add more inlets, but only two are required.

For FDCs serving standpipe or combination standpipe/sprinkler systems, typically found in buildings that are four or more stories tall (or below ground), each FDC is required to have one 2.5-inch inlet for every 250 gpm of demand required by the standpipe system  per NFPA 14 (2019) §7.12.3. The total demand for a system is determined by the number of risers provided on the system. For Class I and Class III standpipe systems with a single riser, a minimum flow rate of 250 gpm out of the two most remote hose connections (total of 500 gpm) is required. For a system with two standpipe risers, this adds an additional 250 gpm for the next riser (total of 750 gpm). As more standpipe risers get added, the quantity increases 250 gpm per additional riser for floors with areas of 80,000 sqft or less. Where floor area exceeds 80,000 sqft, the rate is 500 gpm for the second standpipe and 250 gpm additional for the third. The maximum total flow rate – regardless of the number of standpipe risers – for a sprinklered building is 1000 gpm, and 1250 gpm for a non-sprinklered building.

As most buildings with standpipes have at least two exit stairs, generally when using 2.5-inch inlets it is expected that there will be three 2.5-inch inlets (for 750 gpm standpipe demand). For three or more stairs, four 2.5-inch inlets (maximum 1000 gpm for a sprinklered building) would be expected. The demand for the sprinklers does not have to be added to the standpipe flow to determine the number of inlets.

While Storz inlets, which typically come in 4-inch or 5-inch sizes, are permitted for use, their flow rates are not addressed in NFPA 14 2019 or earlier editions. The proposed 2023 edition; however, will address the flow rates for both 4-inch and 5-inch Storz inlets. A new Section 10.7.3.1.1 states that the flow rate for a 4-inch Storz inlet assumes a flow of 500gpm per inlet and the new Section 10.7.3.1.2 states that the flow rate for a 5-inch Storz inlet assumes a flow of 750gpm per inlet.

 

 

Emergency backup power systems are an imperative component of a buildings Fire Protection and Life Safety (FPLS) systems. Both emergency power and legally required standby power are vital in ensuring essential life safety components continue to operate in the event of an emergency, and first responders are provided with all necessary tools and building functions to facilitate emergency operations. These systems typically consist of emergency generators, automatic transfer switches (ATS), backup battery power, and all associated wiring and equipment.

As outlined in our previous insights (Life Safety Systems Maintenance Parts 1 and Part 2), there has been a renewed focus in the City of Boston on the code-required testing and maintenance related to FPLS systems. This insight seeks to outline these requirements as they relate to emergency power supply systems (EPSS).

What are emergency power supply systems?

NFPA 70, National Electrical Code, outlines the three types of emergency and standby power systems: emergency, legally required standby, and optional standby power. Only the first two are code required under NFPA 110, Standard for Emergency and Standby Power Systems, with emergency power being provided for systems that are essential to life safety, and legally required provided for systems that assist in firefighting operations, or systems whose failure could result in increased hazards within a building during an emergency. Optional standby power is provided for systems that are not essential to life safety or rescue operations, but that may be imperative for day to day operation of a business or facility. This includes data-processing systems, refrigeration units, or other industrial processes. For further insight on these different systems, please visit (https://coderedconsultants.com/insights/emergency-and-standby-power/)

What are the maintenance requirements?

The Massachusetts Comprehensive Fire Safety Code (527 CMR 1.00) requires owners, operators, or occupants to provide tests and to keep records of all maintenance, inspections, and testing of fire protection systems, fire alarm systems, smoke control systems, and emergency power equipment until their useful life has been served, as required by law, or as required by the Authority Having Jurisdiction (AHJ), Sections 10.2.5 and 10.2.6. Periodic testing of emergency power supply systems is described in NFPA 110, Standard for Emergency and Standby Power Systems.

Chapter 8 of NFPA 110 outlines the requirements for emergency power system maintenance, stating that a routine maintenance and operational testing program should be implemented based on manufacturer’s recommendations, equipment instruction manuals, requirements of the AHJ, and the minimum requirements of NFPA 110. Some key requirements outlined in NFPA 110 are as follows:

  • Transfer switches: Periodic maintenance, including visual inspection, cleaning, replacement of contacts. Monthly operation, consisting of operating the switch from the primary to the alternate position and back again.
  • Paralleling gear: Periodic maintenance, including visual inspection, cleaning, and replacement of contacts.
  • Storage Batteries: Weekly inspection to ensure manufacturer’s specifications are met.
  • Generators (EPSS): Weekly inspection of generator components. Monthly operation consisting of the following;
    • Diesel Generators: 30-minute minimum test, using one of the following criteria.
      • Load that maintains the minimum exhaust gas temperature, as recommended by the manufacturer.
      • Under operating temperature conditions, and at a load not less than 30% of the EPS standby nameplate kW rating.
    • Spark-ignited Generators: Tested at the available EPSS load for 30 minutes or until the water temperature and oil pressure have stabilized.
    • For all generators, the date and time of the operational testing is at the facility managers discretion, to not disrupt or interfere with normal building operations.
    • All EPSS operational tests shall be initiated by the ATS, either by the ATS simulating a loss of normal power or by opening the normal breaker to the ATS. Where multiple ATSs are used as part of an EPSS, the ATS used to initiate a test will be rotated monthly.
    • An annual fuel quality test shall be performed per the appropriate ASTM standard.

Also outlined in Chapter 8 of NFPA 110 is the importance of creating and maintaining records of all EPSS inspections, testing, and maintenance. This should include the date and time of all testing, identity of the service personnel, any notes on the condition of equipment, and any corrective actions needed to be taken. These records should be maintained at the discretion of the facility manager and the AHJ.

 

 

Most newly constructed multi-story buildings are designed with elevators to provide both movement and accessibility benefits within a facility. With that said, elevators and their associated hoistways can present significant fire and smoke spread challenges if not properly protected. For this reason, current model building codes require hoistways to be fire resistance rated unless an exception is met. A 1- or 2-hour fire resistance rating is required which is dependent on the number of floors connected by the shaft (1-hour if less than 4-stories; 2-hour if 4-stories or more), and the fire resistance rating of the floor assemblies within the building.

Standard elevator hoistway doors are constructed to be fire rated for compliance with the criteria noted above; however, are typically not designed to limit floor-to-floor smoke spread. As such, building codes have supplemental requirements for hoistway opening protection at or around the elevator car doors. In fully sprinklered buildings, this applies to elevator hoistways connecting more than 3-stories and having either of the following conditions apply (780 CMR 3006.2):

  • The building contains one of the following special Institutional occupancies: Group I-1 Condition 2, Group I-2, or Group I-3.
  • The building is a high-rise and the hoistway is more than 75-feet in height as measured from the lowest floor to the highest floor of the floors served by the hoistway.

If triggered by the above, the following elevator hoistway opening protection options are available (780 CMR 3006.3):

  • An enclosed elevator lobby consisting of smoke partitions is provided at each floor (except at the level(s) of exit discharge) to separate the hoistway from the floor. Lobby doors are required to be self-or-automatic closing, positive latching, and listed as smoke and draft control assemblies per UL 1784. Duct and air transfer openings penetrating a lobby require smoke dampers unless an exception is met.
  • Provide additional doors at each elevator hoistway car door opening at each floor (except at the level(s) of exit discharge) that are operable from the car side without a key, tool, or special effort. The doors are also required to be listed as smoke and draft control assemblies per UL 1784 when tested without an artificial bottom seal. It is common to see elevator smoke curtains used for this application.
  • Pressurize the hoistway with a smoke control system in accordance with 780 CMR 909.21.

Note: Specialty elevators such as fire service access and occupant evacuation elevators have separate and more stringent requirements that must be evaluated separately.