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loadbearing wall

Firestop

[fahyuhr-stop]

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

Materials

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

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

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"

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

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

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

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. Re-entries of fire barriers by most local building codes require the application for and issuance of a building permit from the Authority Having Jurisdiction. Re-entries must be recorded and re-sealing 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.

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 re-seal firestop re-entries in such a manner that the repair is still covered by the original certification listing.

Tagging

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

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:

Germany:

See also

References

External links

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