Forty calls for assistance were made while firefighters were on strike between 2pm on Saturday and 2am on Sunday.
Retained crews manned fire engines across the county while the FBU members walked out in a dispute over changes to pensions and the retirement age.
A spokesman for Lancashire Fire and Rescue Service said that while most of the calls were to false alarms and small fires involving rubbish or in the outdoors, there had been two serious fires and a malicious call.
One incident involved two barges on the Leeds-Liverpool canal in Burscough at 12.33am on Saturday, and there was also a fire involving three adjoining garages in Taunton Road, Blackburn, at 5pm on Saturday.
In addition, crews from Ormskirk, Tarleton and Bamber Bridge were mobilised to reports of a kitchen fire that had the potential for a person to be trapped. This turned out to be a malicious call.
Further industrial action takes place today between 10am and 3pm.