The fourth strike in the firefighters dispute with the Government over pensions takes place tomorrow.
Crews will walk out from 10 am to 2 pm and again stand-by crews will be providing a limited service.
Fire Brigades Union general secretary Matt Wrack said: “After 35 years of service — and paying at least £4,000 a year — firefighters could now receive just over £9,000 a year or the sack simply because fitness declines as they get older.
“Firefighters simply want an affordable and workable pension that reflects the job we do.”
Most firefighters take home approximately £1,650 a month. Most already pay £320 or more a month into their pensions, and from April 2014 this will rise to over £340 a month (£4,000 a year).
The FBU said that the pension proposals are designed to fail because they ignore the physical demands of the firefighters’ occupation.
It said evidence suggested at least two thirds of the current workforce would be unable to maintain the fitness standards required by the fire service beyond the age of 55.
Such firefighters would face the prospect of being dismissed or seeing their pension reduced by almost half, according to the union.
West Yorkshire Fire and Rescue Service said it has robust contingency plans in place tomorrow.
Assistant Chief Officer, Dave Walton, said: “During the three strike periods that have already passed this year our contingency plans have proved effective and we are confident of the strategies that have been put in place for this kind of scenario.
“Tomorrow’s strike action falls during the working day when commercial premises will be in full swing.
“We therefore ask business owners and workers to be vigilant to reduce the risk of fire and keep themselves safe on the roads.“