一分鐘了解英國建材阻燃標準BS476-7完整測試流程BS476-7是英國的一項建筑材料防火測試標準，全稱為建筑材料和結構的著火試驗-第7部分：產品火焰表面延伸等級確定的測試方法。該標準主要用于測定墻面、保溫材料、天花板等建筑材料暴露表面的火焰延伸情況。BS476-7測試流程主要包括以下步驟：樣品準備：數量要求：應提供9個測試樣件，這些樣件需能夠代表此類產品的外露表面。尺寸要求：測試樣件應為885mm×270mm的矩形，并且厚度不大于50mm。設備調試與預熱：安裝測試設備：確保燃燒箱、燃氣輻射板、中型燃氣噴燈、試樣支架等設備安裝正確且連接穩固。其中，輻射板面積通常為850mm×850mm，試樣支架需垂直于輻射板。調試燃氣供應：調節燃氣和空氣的流量，以保證燃氣噴燈和輻射板能夠正常工作，并且火焰強度符合標準要求。輻射板的輻射強度在離75mm處應為32.5kW/m2（表面），噴燈的火焰高75-100mm。預熱輻射板：點燃輻射板的著火點，進行預熱。通常預熱時間為15分鐘，預熱結束后需熄滅輻射板。測試操作：放置樣品：將準備好的樣品放置到樣件固定器上，注意樣品與輻射板的相對位置，確保樣品能夠充分暴露在輻射熱源下。點燃與計時：點燃輻射板，在5秒內將樣件固定器轉到與輻射板面成90°角的位置，同時立即啟動定時裝置，開始測試。點燃樣件，之后馬上啟動定時裝置即開始試驗。在開始試驗后1分鐘內熄滅樣件上的引燃火焰。觀察與記錄：持續用輻射板上的熱量輻射樣品，觀察樣品是否燃燒。沿著材料記錄下在水平參考線位置的持續燃燒和蔓延的火焰跨過每根垂直參考線的時間。記錄在測試開始后第一個1.5分鐘內，火焰蔓延的最大程度；在整個測試過程（最長10分鐘）中，火焰蔓延的最大程度以及火焰最大蔓延所達到的時間和距離；在引燃火焰仍然小于50毫米時，任何延伸不到50毫米的火焰蔓延情況。測試結束：當火焰頭到達825mm的參考線時，或經過10分鐘后（以較短者為準），終止試驗。將樣件固定器轉到備用位置，取下樣品殘留部分，并清理樣件固定器上的碎屑等。以上測試流程需嚴格按照標準要求進行操作，以確保測試結果的準確性和可靠性。測試完成后，根據記錄的數據將被試材料按火焰傳播的程度分為4個等級。LearnthecompletetestingprocessoftheBritishbuildingmaterialsflameretardantstandardBS476-7inoneminuteBS476-7isaBritishfireteststandardforbuildingmaterials.ItsfullnameisFireTestsforBuildingMaterialsandStructures-Part7:TestMethodsforDeterminingtheSurfaceExtensionofFlamesofProducts.Thisstandardismainlyusedtodeterminetheflameextensionofexposedsurfacesofbuildingmaterialssuchaswalls,insulationmaterials,andceilings.TheBS476-7testprocessmainlyincludesthefollowingsteps:Samplepreparation:Quantityrequirements:9testspecimensshouldbeprovided,whichshouldberepresentativeoftheexposedsurfacesofsuchproducts.Sizerequirements:Thetestspecimenshouldbearectangleof885mm×270mmandthethicknessshouldnotexceed50mm.Equipmentcommissioningandpreheating:Installtestequipment:Ensurethatthecombustionbox,gasradiationpanel,medium-sizedgasblowtorch,samplebracketandotherequipmentareinstalledcorrectlyandconnectedfirmly.Amongthem,theareaoftheradiationpanelisusually850mm×850mm,andthesamplebracketmustbeperpendiculartotheradiationpanel.Debugthegassupply:adjusttheflowofgasandairtoensurethatthegasburnerandradiationpanelcanworknormallyandtheflameintensitymeetsthestandardrequirements.Theradiationintensityoftheradiationpanelshouldbe32.5kW/m2(surface)atadistanceof75mm,andtheflameoftheburnershouldbe75-100mmhigh.Preheattheradiationpanel:ignitetheignitionpointoftheradiationpanelforpreheating.Thepreheatingtimeisusually15minutes,andtheradiationpanelneedstobeextinguishedafterthepreheating.Testoperation:Placethesample:Placethepreparedsampleonthesampleholder,payattentiontotherelativepositionofthesampleandtheradiationpanel,andensurethatthesamplecanbefullyexposedtotheradiationheatsource.Ignitionandtiming:Ignitetheradiationpanel,turnthesampleholdertoapositionata90°angletotheradiationpanelsurfacewithin5seconds,andimmediatelystartthetimingdevicetostartthetest.Ignitethesample,andthenimmediatelystartthetimingdevicetostartthetest.Extinguishtheignitionflameonthesamplewithin1minuteafterstartingthetest.Observationandrecording:Continuetoradiatethesamplewiththeheatfromtheradiationboardandobservewhetherthesampleburns.Recordthecontinuousburningatthehorizontalreferencelinepositionandthetimeforthespreadingflametocrosseachverticalreferencelinealongthematerial.Recordthemaximumextentofflamespreadwithinthefirst1.5minutesafterthetestbegins;themaximumextentofflamespreadandthetimeanddistancereachedbythemaximumflamespreadduringtheentiretestprocess(upto10minutes);anyflamespreadthatextendslessthan50mmwhentheignitionflameisstilllessthan50mm.Endoftest:Terminatethetestwhentheflameheadreachesthe825mmreferencelineorafter10minutes(whicheverisshorter).Turnthesampleholdertothestandbyposition,removetheremainingpartofthesample,andcleanthedebrisonthesampleholder.Theabovetestprocessmustbestrictlyoperatedinaccordancewithth