Brandväggar : Litteraturstudie samt enkät- och intervjustudie om branschens erfarenheter och synpunkter

Sammanfattning: In accordance with BBR 29 regulation 5:244, firewalls must with sufficient reliability be ableto constrain a fire without the intervention of the fire rescue service. The wall must alsowithstand probable mechanical impact in the event of a fire. The guidance section for regulation5:244 then declares an M-class to verify the resistance of a probable mechanical impact to afirewall. To achieve the M-class, the firewall must be tested and approved according to thestandard SS-EN 1363-2 which is briefly explained as a 200 kg pendulum that is released froma specified height which impacts the fire-exposed wall three times at the end of the test period.The test method is perceived as unrealistic and has been questioned by the industry. Thepurpose of this study was therefore to examine the current norms and problems regardingfirewalls and the associated M-class. The study includes a survey (50 respondents), aninterview study (10 respondents) and a literature study. The literature study examined theregulations regarding the M-class in Sweden, Norway, Denmark, and Finland. All the countriessurveyed had requirements of M-classed firewalls in their construction regulations. The areaof fire sections, fire alarms and automatic fire sprinkler system were all factors in terms ofrequirements for firewalls and M-class. Sweden is the only country in which combustibleinteriors are allowed on firewalls.The survey was answered by 50 respondents, of which 76% were fire- and risk managementconsultants. The remaining respondents worked as construction engineers, rescue services orothers. The interview study involved 10 respondents, three of whom were fire- and riskconsultants, two were construction engineers, two were from the fire rescue service, and theremaining three worked as product suppliers, test performers and in government agencies. Theresults from the two studies proved that although firewalls are still a common method in firesafety design, eight out of ten respondents answered that the state of knowledge within thesubject is too low. Approximately half of the respondents from the survey knew how the Mclassare verified through SS-EN 1363-2. It emerged during both the survey and the interviewstudy that the interpretation of the minimum dynamic load that corresponds to “probablemechanical impact” as stated in the regulation 5:244 varied between the respondents. Ascattered interpretation was also identified regarding the paragraph of regulation 5:244 whichstates that buildings on either side of the firewall must be able to collapse without affecting theproperties of the firewall. Some of the respondents has the opinion that theM-requirement in the guidance section also satisfies the regulation above.iiBoverket, (Swedish National Board of Housing, Building and Planning) states that therequirement of the firewalls ability to withstand a collapse from buildings on either side of thefirewall, is in most cases not satisfied only by the M-class. Despite the industry's scatteredinterpretation of the requirements, most respondents believe that the benefits of the M-class inmost cases outweigh the cost. Several respondents stated that the test standard SS-EN 1363-2contributes to a qualitative comparison between firewalls and that a wall that passes the testmay be more suitable as a firewall than a wall that does not, but if the test is to reflect a morerealistic scenario, it should be performed differently.