PITTSBURGH (AP) _ Firefighters who can't stand the summer heat won't be allowed to get out of the firehouse and relax in chairs outside the station - with or without Dalmatians.

Fire Chief John Leahy has ordered the city's 1,026 paid firefighters to stay inside the station with the doors closed when not responding to alarms this summer.

''I don't want them outside,'' Leahy said. ''They can be doing constructive work, maintenance, training. There are better things for them to do.''

The order was issued in part to prevent thieves from stealing radios and other equipment from firehouses, he said. It was issued initially last August, but not enforced until this week, with hot and humid weather reaching Pittsburgh.

Bernie Burns, president of Local 1 of the International Assocation of Firefighters, said Wednesday he believed Leahy is reacting to recent news reports of laziness among other city employees.

''It seems there is a new image that the chiefs all over the country are trying to develop,'' the union leader said. ''If he's trying to upgrade the image of the firefighters, I'm certainly not opposed to that.''

''I am trying to improve training and professionalize the job,'' Leahy said.

About a third of the city's 37 fire stations are air-conditioned, said Deputy Fire Chief John Moran, and the stations not air-conditioned have ''fans and windows.''

The only exception to Leahy's rule is that firehouse commanders can open the doors if it's extremely hot and the station has poor ventilation. Some firefighters have brought their own portable air conditioners into stations for the summer, Moran said.

Sitting outside fire houses ''is somewhat of a traditional type of thing,'' Moran said. ''This (order) is a break with tradition.''

Firefighters already have duties other than responding to fires, but ''the whole day is not spoken for,'' he said.

Leahy said he has not received any complaints about his order and other officials said it is being followed.

''They are following it and abiding by it,'' said Battalion Chief Ronald Boggess. ''But no one seems to know the reason. Everyone is questioning why.''