Le hoja ka bobeli li le "C" - li bōpehile, lintlha tsa tsona tsa sefapano - likarolo le matla a sebopeho li fapane haholo, tse amang mojaro oa tsona ka ho toba - bokhoni ba ho jara le boholo ba kopo.

Karolo ea sefapano sa C Channel keho chesa - phuthoa mohaho oa bohlokoa. Websaete ea eona (karolo e otlolohileng ea "C") e teteaneng (hangata 6mm - 16mm), 'me li-flanges (mahlakore a mabeli a rapameng) li pharalletse ebile li na le moepa o itseng (ho thusa ho chesa - ho roala). Moralo ona o etsa hore karolo ea sefapano e be le khanyetso e matla ea ho koba le ho tiea ha torsional. Ka mohlala, 10 # C Channel (e nang le bolelele ba 100mm) e na le botenya ba marang-rang ba 5.3mm le bophara ba flange ba 48mm, e ka khonang ho jara boima ba fuluru kapa marako mohahong o moholo.

C Purlin, ka lehlakoreng le leng, e entsoe ka ho kobeha ho batang ha lipoleiti tse tšesaane tsa tšepe. Karolo ea eona ea sefapano e "slim" ho feta: botenya ba marang-rang ke 1.5mm - 4mm feela, 'me li-flanges li moqotetsane' me hangata li na le mameno a manyenyane (a bitsoang "likhopo tse matlafatsang") metseng. Likhopo tsena tse matlafatsang li etselitsoe ho ntlafatsa botsitso ba sebaka sa li-flange tse tšesaane le ho thibela deformation tlas'a meroalo e menyenyane. Leha ho le joalo, ka lebaka la thepa e tšesaane, khanyetso e akaretsang ea torsional ea C Purlin e fokola. Mohlala, C160 × 60 × 20 × 2.5 C Purlin (bolelele × bophara ba flange x bophahamo ba tepo × botenya) e na le boima ba 'mele bo ka bang 5.5kg ka mithara, e bobebe ho feta 10# C Channel (hoo e ka bang 12.7kg ka mithara).