If the compartment is more than one deck below the weather deck, or the exhaust trunking does not provide a free flow for the used air, a forced exhaust is fitted instead of a natural one.
Ukuba ikhompathimenti ngaphezulu komgangatho ongezantsi kwemozulu yomgangatho, okanyo udabalaliso lwendlela enkulu engakwazi kunika ngokungebhatalisiyo kugalelo lokusetyenziswa komoya, inkani yodabalaliso olulinganiswe ngaphaya kolona lululo.