Loaʻa nā maikaʻi o nā mīkina lima nitritr a me nā mīkina lima PVC. Hoʻopomo ʻia lākou i nā mea maka i kāwili ʻia. ʻO ka papa o loko o nā mīkina lima e maʻalahi a maʻalahi hoʻi e komo. ʻOi aku ka maikaʻi o nā kāʻei lima ma mua o nā mīkina lima o PVC a haʻahaʻa ka uku. ʻO ka papa waho o ka mīkina lima he coefficient o ka hakina, maʻalahi e hoʻohana, a hōʻea i ke kūlana o ka laumania i waho a me ka ʻoluʻolu o loko.