Smokers who would like to join the Alexandria Fire Department as fire fighters had better make a New Year's resolution to quit puffing.

The department, in a regulation that may be the first of its kind in the nation, is requiring as a condition of employment that new fire fighters sign papers pledging they will not smoke on or off duty.

Alexandria Fire Chief Charles Rule explained that under Virginia's Heart and Lung Act fire fighters who suffer from pulmonary diseases or heart attack are presumed to be incapaciated as a result of their job and can thus retire with an extra large pension.

"It's a known fact that smoking is hazardous to your health, so why should we subsidize the deterioration of the heart and lungs and eventual suicial death," Chief Rule said yesterday.

The chief emphasized that he is not trying to impose his personal beliefs on anyone - he was a pipe smoker for 23 years until he quit last July. He and other Alexandria officials said they were trying to protect the firefighters' health and save the city money.

Alexandria personnel director Rolfe E. Schroeder said that in the last three years the majority of disability cases in the city have been due to heart and lung diseases and that this has cost the city an additional $180,000 in pension benefits.

Spokesman for the Fairfax County and District of Columbia fire departments said yesterday their departments were studying the Alexandria regulation with an eye to implementing a similar rule. But Montgomery and Prince Georges County fire officials said they had no plans to impose such restrictions.

Sgt. Kenneth Jones of the Fairfax County Fire Department said he recently completed a report on the department's physical fitness program and added that an Alexandria-style smoking ban is "under consideration and review."

Alexandria's Chief Rule said this was an appropriate time to issue the smoking regulation because the department has been in the process of reviewing its medical standards and is in the process of hiring 12 new fire fighters. The chief said 10 new fire fighters had begun work on Monday and all had agreed to sign the papers stating they would not smoke.

Of the 10, however, only Michael Webster, 22, was a smoker. Webster said yesterday that he had wanted to become a fire fighter since he was 10 years old and did not mind giving up smoking to achieve his goal. He said he smoked a pack of cigarettes a day before he quit Nov. 30 and had often tried to quit smoking before.

"It's going pretty good," he said of his latest attempt. "I haven't touched a cigarette yet. Close, but not yet," he added.

Webster said he does not believe the fire department is infringing on his personal rights by forbidding him to smoke, but he also admitted that if he wanted to he could probably get away with smoking off duty.

The constitutionality of the new regulation is uppermost on the minds of Alexandria officials, but they say they are confident that the rule would withstand a court test. Asked what constitutional problems he foresaw, personnel director Schroeder replied: "I'm not sure that there are any. We place all kinds of conditions on people in terms of employment." Schroeder explained that Alexandria has weight requirements for all fulltime city employees.

Lawrence Selden, chairman of the board of the Northern Virginia chapter of the American Civil Liberties Union, said he was 'shocked' by the smoking prohibition during off duty hours, but added that he would have to study the issue carefully before making a judgement as to its constitutionality.

Chief Rule said the smokers ban came about as a result of consultations with Dr. Paul O. Davis, who heads a private consulting firm on the physical fitness of public safety employees and who helped develop the Alexandria department's fitness program.

Davis said laboratory tests show conclusively that the on-the-job performance of firefighters who smoke fails to measure up to the performance of non-smokers. Furthermore, Davis said, fully half of the firefighters who die on the job die of heart attacks.

Davis has compiled figures showing that the direct cost to a city for one firefighter who retires because of heart or lung disease is $250,000 a year.