text: Additionally , there are volunteer firefighters ( who are theoretically unpaid ) and retained firefighters ( sometimes called on call or auxiliary firefighters , who are paid for the specific time they are on duty , i.e. permanent part-time career firefighters ) on call 24 hours a day , 7 days a week . In such countries as the United Kingdom and Ireland , the use of additional retained firefighters is standard .
simplified: These are called structural firefighters .