Fire Brigades Union general secretary Matt Wrack said: “We have wanted to settle our dispute for a long time, but the government at Westminster is simply not listening.
“Despite endless assurances they have done precisely nothing to address the threat to firefighters as their fitness declines in their 50s.
“Firefighting is a dangerous and physically demanding job which requires specific fitness standards.
“It is obvious to everyone that it is more and more difficult to meet those standards in your 50s compared to your 20s.
”Firefighters in that position face a stark choice of being sacked or losing half their pension.”
The strike will be the 15th taken by members of the union.