Me yasa ake yanka naman da naman yankakken duk birgima?

Ana birgima naman da yankakken naman yankan naman yanka, galibi saboda dalilai guda biyu:

Ɗayan shine yanke kusurwar ruwa. Wutar yankan wuka ce mai kaifi ɗaya. Babban kusurwa shine wannan siffa, yawanci tsakanin 45° da 35° m kwana. Matsakaicin yana rinjayar tasirin mirgina kai tsaye. An daidaita wannan bisa ga mai amfani, irin su gidan cin abinci na barbecue, akasin haka, an yanke shi a cikin wani birgima a babban kusurwa, kamar gidan cin abinci na tukunyar zafi wanda ke buƙatar sanya shi a kan faranti.

Sauran shine zafin naman nama. Yawancin lokaci, ana fitar da naman daga yanayin daskarewa, yanayin zafi yana da ƙasa, taurin yana da girma, kuma ba za a iya yanke shi kai tsaye ba. Daya shi ne wukar ta samu rauni, daya kuma naman yana saurin karyewa. Dole ne a narke shi zuwa yanayin da ya dace na -4 °. Dangane da yanayin yanayi da zafin jiki na wancan lokacin, saboda yawan zafin da ke tsakanin kudu da arewa, lokacin narke ya yi tsayi, kuma naman zai yi laushi da wuyar samu. Akwai hanyoyi da yawa na narke.