London Fire Brigade said it received 124 x 999 calls during the strike period, and contingency crews attended 17 incidents in the capital, including the large fire at a Dagenham scrap metal yard.
The Fire Brigades Union has accused the Government of not listening to its own evidence which shows proposed pension changes are "unworkable and unaffordable".
The Government said the strikes, due to take place from 6.30pm to 11pm today, were damaging the reputation of the fire service.
The general secretary of the FBU, Matt Wrack, said: "It is ludicrous that after two years of negotiations the Government has still not sorted out this mess.
"Firefighters are keen for these issues to be resolved through discussion but the Government won't even listen to its own evidence which highlight that the schemes are unworkable and unaffordable."
Mr Wrack called on the Government to help deliver a pension scheme which takes account of the "hazardous nature of the job" and is affordable and workable for the taxpayer.
Fire brigades across the country have urged people to put off any firework displays in their gardens tonight and to switch it to Saturday, or to go to an organised event as firefighters go on strike in a row over pensions.
London Fire Brigade said today was likely to be one of the busiest days of the year for the fire service, ahead of Guy Fawkes Night and Diwali celebrations and urged people to attend organised displays.
London Fire Commissioner Ron Dobson called on people not to put themselves at risk by lighting fireworks and bonfires tonight as only serious emergencies will be attended to by a contingency fire and rescue service during the strike.
The Fire Brigades Union said it has timed the strikes so that celebrations on Bonfire Night and the Saturdays before and after November 5 - the most popular times for firework displays - can take place.
South Yorkshire Fire and Rescue said its emergency response service would be "severely reduced" because of the strike.