Difference between revisions of "Firestop"

Latest revision as of 09:20, 20 September 2010

A firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings.

Unprotected openings in fire separations void the fire-resistance ratings of the fire separations that contain them, allowing spread of fire past the limits of the fire safety plan of the entire building. Firestops are designed to restore the fire-resistance ratings of rated wall and/or floor assemblies by impeding the spread of fire through the opening by filling the openings with fire resistant materials.

Opening types

• Electrical through-penetrations
• Mechanical through-penetrations
• Structural through-penetrations
• Unpenetrated openings (e.g. openings for future use)
• Re-entries of existing firestops
• Control or sway joints within fire-resistance rated wall or floor assemblies
• Junctions between fire-resistance rated wall or floor assemblies
• "Head-of-wall" (HOW) joints, where non-loadbearing wall assemblies meet floor assemblies

• 07840drw1.jpg

  Typical drawing intended to accompany a firestop specification Section 07840.

• Firestop diagram.jpg

  Typical drawing intended to accompany a firestop specification Section 07840.

• Mortar tag.jpg

  Firestop Mortar seal at a paper mill in British Columbia, Canada.

Materials

Firestop materials include, but are not limited to the following specialised products and devices:

• Intumescents
• Firestop mortars
• Firestop silicones, both one-part and two-part
• Firestop pillows
• Mineral fibres
• One-, two-, and three-part firestop rubber compounds

• Test in flight.jpg

  Fire test of firestop mortar, in flight.

• Timberpen.jpg

  Typical through-penetration in a timber building. Holes are cut by chainsaw.

• Mortpic.jpg

  Firestop Mortar Training, using a Positive Displacement Pump.

• Mortar sequence.jpg

  Cross barrier entirely built with firestop mortar.

• Marine firestop.jpg

  Firestopping aboard a ship. It utilises a German "Kaltvergussmasse", which is an inorganic powder mixed with liquids to form a solid, through hydration.

• Ppd and kfg.jpg

  Intumescent plastic pipe devices intended to squeeze a melting pipe shut during a fire. Openings here are oversized and have been narrowed down using a certified firestop mortar.

• Sl silicone pipe covering.jpg

  Mechanical pipe through-penetrations in 2 hour slab with metallic piping, covered through the thickness of the firestops with 25mm thick rockwool pipe covering with foil scrim kraft facing as vapour barrier.

• Stuffed rockwool firestop.jpg

  Inappropriate attempt at firestop using rockwool

Ratings

A common misunderstanding of firestops is that certain materials have certain ratings on their own. For instance, a two-hour rated pipe penetration firestop may consist of a 5 mm layer of caulking, over top of 100 mm of packed rockwool. The layman may assume that the 5 mm layer of the caulking provides a two hour fire-resistance rating, generically, regardless of the application, which is incorrect. Materials are not individually rated. Instead, they are used as components within an overall system or certification listing. In addition, all materials in and around the firestop must employ listing and approval use and compliance such as to conform to the tolerances shown in the certification listing that covers each such installation, including the penetrants, which may have their own product certification requirements apart from forming part of a certification listing for a firestop.

Compatibility

All items within a system that touch one another should have proven compatibility both under fire conditions and operational conditions. For instance, sealants should not degrade penetrants. Cold penetrants may attract dew. Such penetrants should not be in contact with sealants that easily degrade in the presence of water. Also, building joint firestops may achieve very high fire-resistance ratings when tested between two concrete elements with insulation in the middle. Sealants with ratings of B2 per DIN4102 (like timber - normal combustibility) or even B3 per DIN4102 (easily ignited like polyurethane foam) can survive up to 4 hour fire tests because they are protected by rockwool on the exposed side. In reality, however, penetrants are often found within building joints, which are equally sure to conduct considerable heat through to the unexposed side and right into the sealant (see T-ratings in the certification listing article). To avoid any heat induced degradation, let alone spontaneous combustion, one can simply restrict joint sealants to those that have already achieved ratings in service penetration firestops.

Common problems and solutions

It is important that firestops be used in accordance with the listing and approval use and compliance. Documentation for each construction site should exist, including an inventory of all firestops in a building, identification tags and a separate set of drawings showing each firestop and the certification listings used for each installed firestop. Unless this documentation is called for during the planning stages, created during construction and turned over in its entirety to the owner, along with comprehensive training for maintenance purposes, the owner has no way of knowing which hole is firestopped how and why that matters to his or her ability to meet the requirements of the fire code once the building is occupied. Otherwise, proper repairs are guesswork, which violates the fire code.

The collection, turn-over and training of this information for the owner is often not required or completed. Proper documentation is maximised by having one speciality firestop contractor do all of the firestopping on site, allowing co-ordination and collation of the documentation for the eventual turn-over to the owner. Otherwise, up to a dozen different contractors or more could be involved, each using materials from different manufacturers, which are not interchangeable. The owner should be educated of the importance and role of firestopping, and passive fire protection to prevent the most common fire code violations, where firestopping is concerned.

No firestop at all

• Unsealed1.jpg

  Unsealed pipe penetration in 2 hour fire-resistance rated concrete block wall.

• Unsealed2.jpg

  Unsealed pipe penetration in German University.

• Unsealead3.jpg

  Concealed and unsealed cable penetration inside a control room cabinet in Pt. Tupper, Nova Scotia, Canada.

• Unsealed3.jpg

  Unsealed cable penetration right next to a fire door.

• Drywall firestop problem4.jpg

  Unsealed cable penetration, concealed behind T-bar/dropped ceiling — a very common deficiency.

• Cambrian college no firestop 1.jpg

  Improper breach of fire-resistance rated drywall assembly.

Older buildings routinely have no firestops at all. In that case, a thorough inspection helps, which clearly identifies all fire barriers, vertical and horizontal, and their ratings. This should be followed by an examination of all these barriers to find all breaches, inventory them and then seal them with approved methods under the auspices of a building permit.

"Deemed-to-comply"

• Puf.jpg

  Polyurethane foam used to fill a cable tray penetration. At Browns Ferry Nuclear power plant, a seal of this nature resulted in significant fire losses.

• Puf removal.jpg

  Removal of flammable polyurethane foam from cable tray penetration to prepare for replacement with approved firestop mortar.

• Concrete firestop.jpg

  Common concrete with no testing back-up or certification listing is not a proper firestop.

• Boot firestop.jpg

  Bits of polyurethane foam and old rubber boots shoved in the hole does not provide a firestop.

• Stuffed fibreglass firestop.jpg

  Stuffed fiberglass weatherproofing would rapidly melt and fall out in a fire.

• Stuffed rockwool firestop.jpg

  Rock wool weatherproofing is not approved for this application as a stand-alone firestop.

• Cambrian college homemade firestop.jpg

  Fireproofing applied at the wrong time, avoiding code compliance.

• Cambrian college fireproofing delamination 5.jpg

  Example of how spray fireproofing was improperly used to cover penetrations.

• Ye olde oily rag firestop.jpg

  An oily rag is not a firestop.

The "deemed-to-comply" variety of illegal firestops includes homemade remedies, where people invent their own methods without any testing back-up, let alone product certification. These are short term cost cutting measures at the expense of fire safety and code compliance. Common mistakes include citing a listing for products that may be for other uses. For instance, an insulation with an active listing for having a certain flamespread rating does not mean it is acceptable for any other purpose.

Right products, wrong installation

• Elastaseal.jpg

  This firestop is missing the proprietary coating that is intended to be applied on both sides. That step was omitted as a cost-cutting measure. The seal is only listed for maximum 1.1ft² openings.

• Cp25 grand coulee dam.jpg

  Inoperable firestop made of self-leveling intumescent caulking applied in a wall at Grand Coulee Dam.

• Nortown.jpg

  Intumescent collar is applied at the bottom of the plastic pipe penetration. The problem is that the slab is not smooth and the fire can go straight through to the pipe above the collar. This firestop is inoperable.

• Sl silicone lousy packing.jpg

  Self-leveling silicone caulking that should be 13mm thick - this thickness varies from 1mm to 30mm because the packing below is uneven.

• How clusterf.jpg

  HOW Joint with uneven silicone caulking thickness, smeared into place by untrained staff. Status: inoperable.

• Silicone foam sakno1.jpg

  Faulty Sakno Silicone foam installation, Image 1 of 2

• Silicone foam sakno2.jpg

  Faulty Sakno Silicone foam installation, Image 2 of 2

These pictures indicate the desirability for purposely trained firestop installers who know that the installed configuration must conform to an active certification listing. In each of the above cases, the firestops were installed by adjacent trades, either the trade that was responsible for the penetrant or the trade that was responsible for erecting the fire barrier that contains the firestop. Firestopping is a complex matter best left to those who have the resources, training and interest to match up the installed configuration with a listing.

Improper, unenforced specification and trade jurisdiction

• Drywall firestop problem1.jpg

  This case has mixed trade assignments. The plumber hangs a sleeve before the wall is up. The drywaller mounts the sleeve, the insulator is only asked to fill between sleeve and the pipe. The result is not fire-resistance rated.

• Firestop spec problem.jpg

  A combination opening that highlights the desireability for one installer to do all firestopping to ensure compatibility.

• Shaft dupont mississauga on.jpg

  Common combination penetration: a joint firestop with mechanical services. Joint firestops must be cross-listed for penetration seals to avoid this common scenario where urethane caulking could otherwise come in contact with hot steel and autoignite on the unexposed side or at least let go during the hose stream test.

• Nortown plastic pipe drywall.jpg

  The "I-was-there-first-scenario", resulting in improper drywall firestops with plastic piping.

These pictures highlight the need to ensure that firestops are not separate add-ons to mechanical, electrical, masonry, drywall and other trade contracts. All components routinely come into contact with one another. Without having these essentials in place from the start, mechanical and electrical trades who are obliged to do their own firestopping routinely use the "I-was-there-first-scenario" (justification) for absolving themselves particularly of their responsibilities to properly seal drywall through-penetrations, which can be difficult (see drywall article).

Re-entry

• Reentry1.jpg

  Re-entered Firestop Mortar

• Reentry2.jpg

  Re-entered, Dislodged Firestop

• Reentry3.jpg

  Re-entered Cable Tray Penetration With Tagged Firestop Mortar Seal.

• Reentry4.jpg

  Re-entered opening that was created for future use in an electrical service room.

• Reentry5.jpg

  Re-entered Cable Tray Firestop In A Wall With Firestop Mortar. This Side Of the Pic Was Shot From The Operating Floor.

Firestops are often re-entered, throughout the life of a building, as the pictures show. If the intent of the fire protection plan of a building is to remain operable, it is imperative that a plan be in place to ensure that re-entries of firestops are done within the context of a plan that is ideally put in place during the design stage of a building. Reentries of fire barriers by most local building codes require the application for and issuance of a building permit from the authority having jurisdiction. Reentries must be recorded and resealing must be done in the full knowledge of and compliance with the certification listing upon which the original installed configuration was based. This is best accomplished by minimising the number of trades executing firestop work and the number of firestop manufacturers used during the original construction so that the number of repair materials can be kept small and manageable. It is desirable that each opening be properly tagged and correspond with documents that are collected by the design and construction team, turned over intact to the owner and be kept up to date by the owner to ensure compliance with the local fire code.

• Mortar reentry.jpg

  Fire test preparation for proven re-entry procedure with firestop mortar.

• Cp25 reentry.jpg

  Fire test preparation with re-entry of firestop mortar, re-sealing using intumescent firestop caulking for fire-test-proven compatibility between mortar and caulking in the same certification listing.

• Putty reentry.jpg

  Fire test preparation: reentry of firestop mortar with cable and re-sealing with intumescent firestop putty for fire-test-proven compatibility between mortar and putty.

The above gallery shows the consideration required for proven repair procedures. These pictures are of the same test assembly shown in the fire-resistance rating article. The close-ups show that this test established compatibility between the mortar and an intumescent caulking and an intumescent putty. This provides some variety to a building owner who is required to reseal firestop reentries in such a manner that the repair is still covered by the original certification listing.

Tagging

• Firestop tag front.jpg

  Firestop tag front. This identifies information necessary for proper maintenance.

• Firestop tag back.jpg

  Firestop tag back. This side of the tag permits keeping track of maintenance.

Proper maintenance is enhanced by the installation of tags on each side of the firestop, containing the information necessary to reference to documents indicating the approved procedures for the original installation and re-entries. This requires knowledge of the exact certification listing that was used for each opening, be it a building joint or a penetrant through-penetration seal.

Testing and certification

Acceptable certification listings include but are not limited to those available from

• Underwriters Laboratories, or
• Underwriters Laboratories of Canada in North America, or
• Deutsches Intitut für Bautechnik in Germany, or
• Efectis in The Netherlands, France, Norway.
• FM Global provides testing and certification of firestops, and also certification of firetop contractors^[1]

Regulations and compliance

When the installed configuration is not in conformance with the appropriate certification listing, the fire-resistance rating may be less than expected. In those cases in which it is difficult to assess the impact, it often must be assumed to be zero, which means that the fire protection plan for the building is compromised. For any deviations from this principle, one is required by law to contact the Authority Having Jurisdiction (AHJ) to gain acceptance of a suitable remedy.

It is, therefore, necessary to be able to match each opening in fire-resistance rated wall or floor in a building with a certification listing. There are thousands of listings by various certification and testing laboratories. Both the Canadian and US Underwriters Laboratories each publish separate books containing just their own listings, including only those firestop manufacturers who have contracted with them for testing and certification.

Firestops must be routinely inspected and maintained to mitigate the effects of re-entries. Even if not altered, some firestops may fall apart over time, such as North American intumescents based on unprotected sodium silicate without proper approval. The only way to accomplish this and meet the code is to ensure that separate shop drawings exist, which show all fire-resistance rated wall and floor assemblies and their specific ratings.

Trade jurisdiction

In North American unionised construction sites, firestopping is often performed by members of the insulating trades. The insulators are the only building trade that includes firestop installation, theory and practical firestop training within its apprenticeship program.

An agreement exists between the insulators and the electricians IBEW, which assigns firestop work from electricians to insulators, except that composite crews are required when working near live electrical conductors, whereby an electrician is required to observe and ensure the safety of the insulator.

Germany's GBA (Gütegemeinschaft Brandschutz im Ausbau) also offers a passive fire protection course, resulting in a certificate designation: "Brandschutzfachkraft" (~Passive Fire Protection Expert). In Europe as well as North America, all major firestop installers with nuclear installation experience are, by background insulators first. The generic material types used and the skill sets needed between insulation and firestop installations are similar. Exceptions to the generic rule of thumb about firestopping being insulators' work, includes firestop devices that become an integral part of the plumbing system, which must be installed by plumbers during the forming of concrete.

Trade associations

United States of America:

• Alliance for Fire & Smoke Containment & Control
• Firestop Contractors International Association
• International Firestop Council

Germany:

• Gütegemeinschaft Brandschutz im Ausbau

See also

References

1. ↑ http://www.fmglobal.com/assets/pdf/fmapprovals/4991.pdf Approval Standard for Approval of Firestop Contractors, Class Number 4991

External links

• UL Essay On Firestops
• Deutsches Institut für Bautechnik (DIBt)
• iBMB a part of Technische Universität Braunschweig
• Underwriters' Laboratories of Canada (ULC)
• Underwriters Laboratoriesde:Schott

no:Skott pl:Gródź ru:Огнезащита sv:Vattentätt skott