Firestop
From Wikipedia, the free encyclopedia
A firestop is a passive fire protection system of various components used to seal openings in fire-resistance rated wall and/or floor assemblies through bounding, which is based on elaborate fire testing as well as environmental testing, in some cases.
Unprotected or unbounded openings in fire separations void the fire-resistance ratings of the fire separations that contain them and thus, both in practical and legal terms, collapse the fire compartments of which these fire separations form a part, which affects the fire safety plan of the entire building. Firestops are specifically designed to restore the fire-resistance ratings of rated wall and/or floor assemblies by bounding the openings through approved firestops.
Contents |
[edit] 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
 This is a typical drawing intended to accompany a firestop specification Section 07840. Its purpose is to show trade responsibility and to indicate which trade does what when it comes to sealing mechanical, electrical and structural through-penetrations in noncombustible wall and floor assemblies required to have a fire-resistance rating. |
 This is a typical drawing intended to accompany a firestop specification Section 07840. Its purpose is to show trade responsibility and to indicate which trade does what when it comes to sealing mechanical, electrical and structural through-penetrations in drywall assemblies required to have a fire-resistance rating. |
 Firestop Mortar seal at a pulp and paper mill in British Columbia, Canada. Firestop mortars of sufficient strength and depth, at densities not far above 1 kg/L can absorb heat from penetrants and also withstand the heat induced expansion and motion of ferrous cable trays that are exposed to fire. They tend to be noncombustible and easy to install. Notice that this firestop bears an identification tag, with clear bounding references, such as the applicable Underwriters Laboratories certification listing number, to enable intelligent maintenance. |
[edit] Trade jurisdiction
In North American, unionised construction sites, with few exceptions, firestopping is performed by members of the International Association of Heat and Frost Insulators and Asbestos Workers, Lanham, Maryland. 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 an extensive 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 German trade designation is "WKSB)" (Wärme, Kälte, Schall und Brandschutz), an acronym that stands for heat, cold, sound and fire protection. On both sides of the Atlantic, these traditions prevail for good reason, as the generic material types used and the skill sets needed are similar, between insulation and firestop installations. 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.
[edit] 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
 A test assembly after successfully completing a two hour fire-endurance and subsequent hose-stream test. This assembly used firestop mortar, as well as accessories such as intumescents, penetrants including insulated piping and cables. |
 This picture shows a typical through-penetration in a timber building. The plastic pipe is the penetrant. Combustible buildings can have fire compartments, consisting of assemblies capable of achieving a fire-resistance rating. Typically, wall assemblies made of wooden studs, must be boarded with "Type X" or glass fibre re-inforced gypsum wallboard, where the installation must consider bounding. Wooden floors are often topped with thin layers of concrete. Through-penetrations for mechanical or electrical services, as shown here, are not formed by sleeving, but by chainsaws that go right through everything. The determining factor for the penetration sizing in this case is the width of the chainsaw blade. Otherwise it is the size of the penetrant that determines the size of the sleeve or block-out. |
 Firestop Mortar Training, using a Positive Displacement Pump. |
 Images of an industrial firestop installation, with a fire-resistance rated cross-barrier installed in a service tunnel. The sequence of installations reveals the pumped, dimensionally stable firestop mortar, which goes in "rough" and is then smoothed up. The openings around the piping, (penetrants), were sealed with a combination of stuffed rockwool and firestop silicone sealant topping on both sides, for flexibility. |
 Penetrations sealed with intumescent plastic pipe devices intended to squeeze a melting pipe shut during a fire. The openings here are oversized and have been narrowed down using a certified firestop mortar. |
 Faulty Sakno Silicone Foam Firestop Installation in Calgary Sewage Treatment Plant in the 1980's, to seal opening above a fire door in a cast concrete fire separation. This was a winter installation with outdoor temperatures near -40 °C. Now and then, the exterior door was left open, which affected ambient indoor temperatures and thus the "snapping" process of the foam, whose density varied widely within the seal. Silicone foam, once mixed, evolves hydrogen gas, which bubbles, thus creating a foam, as the liquids turn to solid rubber. |
[edit] 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 of the caulking provide a two hour fire-resistance rating, generically, regardless of the application. This is absolutely wrong. The mere notion underlines a fundamental misunderstanding of bounding. Materials are not individually rated. Instead, they are used as but components within an overall system or certification listing, that must provide identifiable bounding for the installed configuration. In addition, all materials in and around the firestop must conform to the tolerances shown in the certification listing that covers each such installation, including the penetrants, which may also have their very own bounding requirements apart from forming part of a certification listing for a firestop.
[edit] Common Problems and Solutions
Users must understand the role of bounding and the role of firestops within passive fire protection and the role this plays within overall fire protection. Exact documentation for each construction site must exist, complete with an inventory of all firestops in a building, identification tags and a separate set of drawings showing each firestop and the bounding provided by 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. One must be able to find the firestops, walk up to them and be able to find a current tag, that is listed on a purpose-designed inventory for each building, showing the certification listing that covers the installed firestop. Otherwise, proper repairs are but guesswork, which violates the fire code. The collection, turn-over and training of this information for the owner is too often absent and is precluded by the practice of having each trade do its own firestopping, whereby the plumber may do some, the electrician may do some, as will the drywaller, and so forth. A separate and complete firestop specification must exist, as well as a line item cost breakout during the tender stage, whereby the firestopper is one sub-contract to the general contractor, whereby one speciality firestop contractor does all firestopping on site, so that he or she can co-ordinate and collate the proper 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 for liability and bounding reasons. With literally thousands of firestops per building, simpler is better. The owner must be given the knowledge to understand the importance and role of firestopping, passive fire protection and bounding to prevent the most common fire code violations, where firestopping is concerned.
[edit] 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.
[edit] Regulations and compliance
When the installed configuration is not in conformance in all respects with the tolerances of the appropriate certification listing, it is not bounded and, therefore, the rating is zero, which means that the entire fire protection plan for the building that contains such a violation of codes, 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 literally 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, whose firestop manufacturers they have under contract. There are at any given time just in North America up to sixty different manufacturers, each with dozens of products, each with many listings. An architect will routinely specify up to ten different manufacturers, whose products are acceptable for use within one construction site. This means several books full of firestop possibilities for just one single building. It is, therefore, entirely logical and highly advisable to label firestops such that one can easily determine bounding, meaning that one is able to look up what listing covers which hole, both on tags on each firestop but also on the shop drawings, which then show all those openings in all the walls and floors, in such a way that they are logically numbered and cross-referenced.
Only in that way, can one perform repairs, which are often necessary. Firestops get re-entered all the time, especially electrical penetrations with penetrants such as cables, conduit, etc., because people often make changes to wiring in particular. Unless one knows precisely what listing covers the firestop in question, one has little chance of being able to determine what materials to use for the repair, or if a new penetrant is even permissible to be used in a sealed opening. Some firestops are listed with repair procedures, others are not. Just because a material "sticks to itself", that does not mean there is any evidence that will hold up in a court of law, that actually proves that a repair was included in the original test. Firestops are routinely misunderstood and incorrectly installed or completely absent. Noncompliances can be deliberate or accidental. Changes to firestops require the notification and approval of the Authority Having Jurisdiction (AHJ), meaning either an acceptance by the fire prevention officer or a building permit.
Firestops must be routinely maintained and kept bounded, not because they otherwise fall apart (though some have been known to such as North American intumescents based on unprotected sodium silicate without proper DIBt approval), but mostly because of re-entries. 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. Next, all building joints and all mechanical, electrical and structural through-penetrations must be shown and numbered on the drawings. Descriptions for each opening must be kept, along with photographic evidence of proper sealing, which identifies each component and the certification listing that covers each installation. Certification listings for firestops are not complicated, but they can be lengthy, with a variety of separate detail drawings.
It is impossible to determine bounding without evidence that the installed configuration is within the tolerances of the applicable certification listing upon which the installation was based. Without this evidence, no proof of building code or fire code compliance can be deemed to exist. Hence, when approaching a firestop, one should be able to see a clear tag that identifies the opening number, which can then be cross-referenced in the overall building's inventory of firestops. Re-entries and repairs must also be documented. Opening numbers found in the field must match those found on the tags. A functional maintenance program must exist, whereby tags are used to identify repair materials and methods, especially in buildings where firestops from more than one manufacturer were used, as there is typically no proven compatibility between firestop materials from different manufacturers, which precludes bounding, which spells fire code violations. That is a very important point. Compatibility between firestops made by two different firestop manufacturers, who compete against one another, has precious little to do with whether or not the two materials bond to one another or whether or not one may in fact help to deteriorate one another. Unless both are included in ONE certification listing, meaning that both have been tested together with the intention and consent of both manufacturers, there is no identifiable bounding, meaning that liability for such a combined seals becomes the responsibility of those who performed and/or authorised the mis-match. Even two different materials made by THE SAME manufacturer, can only be combined in one firestop if a certification listing exists that sanctions the match.
Only with an organised inventory and maintenance scheme does the owner have a chance of being able to provide evidence of compliance, in the event of an inspection or a fire. Tagging is already mandatory in Germany. It is, thus, counter-productive to have multiple contractors in charge of firestopping within one building, as each can typically use different materials and listings, which may or may not be compatible with one another. Unless the contractor who is installing the firestop is an active participant in the firestop industry, meaning that his primary aim is to work in passive fire protection, chances are that bounding details are missed, which jeopardises the entire fire protection plan of the building. While it is possible to achieve the required ratings required to meet the building code using a large number of products, the result becomes hopelessly complex for the owner to maintain afterwards. If the architect permitted the use of products from six (6) different manufacturers, which is not out of the ordinary, who each have twelve (12) different products (which is also not out of the ordinary), which each have 60 listings (which is conservative), the logistics surrounding what governs just one single opening are considerable. To enable reasonable maintenance and documentation for the owner throughout the use of the building, it is necessary for the architect to have a strict master specification in place, which may have to be adjusted to the unique needs of certain buildings, ships or offshore facilities. An appropriate master specification Section 07840 should contain a wide variety of experience-based SPEC-NOTES to remind the specification writer of the requirements for all paragraphs and different project requirements. Just having a Section 07840 will not do though. Pointing each separate trade to it and having everyone do his or her own firestopping is, once again, counterproductive to producing a building where the owner is able to maintain fire code compliance. There is simply too much information to maintain otherwise, which is akin to setting the owner up for fire code violations within weeks or even days of occupancy. It is not unusual for owners to begin to re-enter firestops before the last tradesmen from the original construction have left the buidling. Firestoppers routinely repair firestops during the last days on the job, that have already been altered with new penetrants for tenant work. Without tagging and training of the owner, fire code compliance becomes an illusion from the first day the keys are turned over to the owner.
