The quarterly newsletter from Phoenix National Laboratories that focuses on quality, testing technology, and inspection trends
Business is booming in Arizona and specific enforced special inspections for new construction are on the rise. Firestop special inspections are trending in the architectural requirements of the IBC (International Building Code) construction codes. In the last year, PNL has received a significant increase in requests for both Fireproofing and Firestop inspections primarily due to increased enforcement by local building departments, including the City of Phoenix. With the recent FCIA accredited certification programs for firestopping by both UL and FM, municipal building departments have recently recognized the certifications and critical expertise needed to properly inspect firestopping installations.
Firestop is a technique which applies materials in critical areas, during the building construction phase which prevents the fire from spreading from the site of origination. It is one of the many methods utilized by engineers and contractors to contain the spread of fire and it is important to have inspections to assure compliance with the firestop designs.
PNL is uniquely equipped to provide these inspections performed by our technicians with specific training and experience, beyond the standard civil materials testing scope. Since our primary objective is continuously ensuring the public safety, we are always prepared with up-to-date certifications and experienced technicians.
A fire produces heat that can weaken structural components and creates smoke by-products that cause property damage and place occupants at risk. The Uniform Building Code (UBC) defines building types and the required fire ratings (in hours) for each specific element of the building. Building elements include the Primary Structural Frame, Bearing Walls, Nonbearing Walls and Partitions, Floor Construction, and Roof Construction. The fire ratings are based on building construction type along with building height and area requirements, active fire detection and suppression systems, and occupant egress requirements to contain a fire should it occur, while helping ensure occupants are able to safely exit.
Firestopping and Fireproofing are two methods used to achieve the required fire ratings for specific elements defined by the UBC. Firestopping systems are used at wall, floor, and roof penetrations while fireproofing is typically applied to the primary and secondary members of structural frames, floors, and roofs. Firestop systems and fireproofing materials must be tested in accordance with ASTM or UL standards to assure they meet the required fire ratings specified by the UBC.
A Through-Penetration Firestop System is defined by the UBC as: An assemblage consisting of a fire-resistance rated floor, floor-ceiling, or wall assembly, one or more penetrating items passing through the breaches in both sides of the assembly and the materials or devices, or both, installed to resist the spread of fire through the assembly for a prescribed period of time. This is often achieved through the installation of a membrane constructed using caulks, putties, sealants, foams, and other devices at the penetration.
Fireproofing products protects the structural elements of the building to prevent collapse and irreparable property damage during a fire. It is commonly applied to steel and concrete during the building construction phase with either spray and/or brush. There are two types of fireproofing commonly used, cementitious (mastic) and intumescent. Cementitious products are usually applied to areas that are not visible to the occupants of a building where intumescent products are more architecturally appealing and are applied to components that are visible to the occupants.
Intumescent (epoxy based) fireproofing is a substance that swells as a result of heat exposure, leading to an increase in volume and decrease in density. Intumescent materials are typically used in passive fire protection and require listing approval and compliance in their installed configurations in order to comply with national building codes.
Cementitious fireproofing is a sprayed-on or brushed on fireproofing method that coats structural steel and concrete members to provide passive fire protection and manage the spread of a potential fire. It’s made of a gypsum-based, wet formulation mix and applied on-site in varying thicknesses.
Through penetration firestop systems and fireproofing applications must be inspected by a third party independent special inspector to assure compliance with the plans and specifications. The qualifications of the inspectors are not interchangeable but are considered separately as dictated and approved by the authority having jurisdiction (AHJ) where the building is being constructed, typically, the local city or county building department.
Inspectors who perform cementitious and intumescent fire-resistant coatings will typically possess an ICC Spray -applied Fireproofing or ICC Fire Inspector certificate. The inspection of Sprayed fire-resistant materials are to be in accordance with the IBC and include verifying the condition of the substrate prior to application, testing the thickness, density, and bond strength periodically during application, and verifying the condition of the finished application after rough installation of electrical, automatic sprinkler, mechanical and plumbing systems and suspension systems for ceilings, and before concealment. For intumescent fire-resistant coatings special inspections shall be performed in accordance with AWCI 12-B. Special inspections and tests shall be performed during construction. Additional visual inspection shall be performed after the rough installation and where applicable, prior to the concealment of electrical, automatic sprinkler, mechanical and plumbing systems.
Firestop inspectors will typically be required to have passed either the UL or FM firestop examination. Fire-resistant penetrations and joints are to be conducted by an approved agency in accordance with ASTM E2174 for penetrations and E2393 for joint systems.
PNL is an approved agency for most Arizona building departments and has qualified and certified special inspectors with experience in both fireproofing and firestopping inspections.
In addition to the visual special inspection requirements dictated by the Uniform Building Code (UBC), additional testing is required to verify that cementitious or intumescent fire-resistive materials have been applied properly. These tests include thickness, density, and bond strength tests for cementitious materials and thickness for intumescent materials.
Thickness testing for cementitious fire-resistive materials is performed using a penetration measuring device as shown in Figure 1. It is relatively simple to take measurements using the device, but the acceptance is based on making the measurements in the proper location for each element. AWCI 12-A provides guidance for where to take measurements based on element type. Critical locations include the side of flanges and bottom joist chords, and the sides of flutes for fluted decks.
Thickness for intumescent or primer coatings is performed using electronic coating thickness gauges that use the principles of magnetic and electromagnetic induction to make measurements. Figure 2 shows such a device.
Magnetic induction instruments use a permanent magnet as the source of the magnetic field. A Hall-effect generator or magneto-resistor is used to sense the magnetic flux density at a pole of the magnet. Electromagnetic induction instruments use an alternating magnetic field. A soft, ferromagnetic rod wound with a coil of fine wire is used to produce a magnetic field. A second coil of wire is used to detect changes in magnetic flux.
These electronic instruments measure the change in magnetic flux density at the surface of a magnetic probe as it nears a steel surface. The magnitude of the flux density at the probe surface is directly related to the distance from the steel substrate. By measuring flux density the coating thickness can be determined.
These instruments can contain data loggers which allow a large number of measurements to be taken and downloaded into a spreadsheet or other report.
Density measurements are performed on cementitious material that is removed from an element and dried until the weight is constant after subsequent 24 hour measurements. Density is determined in accordance with ASTM E605 and is given by:
Density = Weight / Volume
The required density is provided in the plans and specifications and is a good method to determine whether the material was mixed and applied properly. After removing material from each element, the area must be patched to maintain the fire rating.
Bond Strength Testing
The bond strength of cementitious material is determined by affixing a cap with a pull hook to the material using a foam adhesive. Once the adhesive is cured, a force gauge is attached and a load applied. The bond strength is given by:
Bond Strength = Applied Force / Area of Cap
This test determines that the material will not easily come off while in-service. Testing is in accordance with ASTM E736 with the required bond strength provided by the plans and specifications for the project.
Fire prevention in commercial and industrial buildings is strategically more comprehensive than simply housing fire sprinkler equipment, fire alarms, fire extinguishers, and installing engineered fireproofing controls. There are important fire safety measures to incorporate in a commercial building fire safety prevention plan.
Building Access & Emergency Evacuation Routes according to OSHA requires doors, windows, and all access in and out of your building to be continually clear so occupants can use emergency evacuation routes to get out and the fire department can get in. Unobstructed doors, hallways, pathways, stairways, and windows must be made accessible. By implementing this daily practice, you address one of the most vital fire safety features in buildings.
Fire Safety Exit signs and Fire Alarms
NFPA 101 (National Fire Protection Association) requires exit signage and lighting be continually illuminated and easily seen, even in a power outage. Exit signs must be bright and free from blockage, emergency lighting units functional, and exit signs and lighting backup batteries should be fully charged and reliable.
Practice Good Daily Habits for Building Fire Prevention
There are several safety habits that should be instituted on a daily basis. These include trash/waste being properly stowed, avoiding doorways, extension cords are unplugged, all power strips are UL listed with built-in circuit breakers, cigarette butts and containers are away from the building, combustible materials/liquids are stored securely in an approved cabinet, electrical appliances are GFCI protected, and nothing is hanging from fire sprinkler piping or sprinkler heads.
Preventative Inspection & Maintenance for Fire Protection Systems
Instituting NFPA 72 and ICC (International Code Council) measures help avoid fines regarding preventative fire protection system inspections. They are your best deterrence against a faulty system that may not operate properly when needed. Preventative, regularly scheduled inspections are required for: fire sprinkler systems, backflow preventer assemblies, fire suppression systems, fire alarms, fire extinguishers, alarms, monitors and detectors.
Train Staff on Workplace Fire Prevention & Safety Measures
While the installation of engineered fireproofing systems can slow the spread of fire, only with fire safety prevention and life-safety training will your employees know how to prevent fires, stop fires, and evacuate calmly in the event of a fire. Compliance with NFPA and OSHA fire-safety standards provide the best fire danger protection for clients and staff. It also ensures your employees understand the primary fire protection requirements for buildings. .
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