Forty-seven persons died in Washington last year as a result of fires, compared to 23 in 1975, D.C. Fire Chief Burton M. Johnson reported yesterday.

Battalion Chief Francis X, Flaherty said there was no real trend apparent in the figures, noting that in 1973 there were 50 fire deaths, three more than last year.

Speaking at a press conference, Chief Johnson said the department is beginning a new educational program aimed at reducing the number of fire deaths by making the public aware of such hazards as careless smoking. The program is also designed to teach methods of curbing the spread of fire and methods of escape, he said.

In answer to questions, Johnson said it was only speculation that some of the fire deaths might have been associated with a program of closing on a rotating basis four of the city's 53 fire-fighting and rescue companies.

However, in an interview, Dave Ryan, head of the firefighters' union, said the program of closings, "certainly hasn't helped."

The program, initiated in 1975 because of manpower shortages and budget constraints was altered last year by the mayor after a public outcry followed fire deaths near the station of a company that was out of service.

All the city's 51 fire fighting companies and one of the three rescue squads are now in full-time service. Two of the fire companies assume the role of rescue squads if needed. Johnson said yesterday that he is seeking to restore the two full-time rescue squads as well.

Meanwhile, the mayor allowed to become law without his signature a City Council approval of major changes in the number or location of fire companies. The measure is still subject to review by Congress.

Similar legislation was enacted by the Council last Oct. 12, about five weeks after the fatal fire at 1258 Neale St NE, which provoked the outcry. However, the mayor vetoed that bill, saying it was too restrictive. He said through a spokesman that the new measure appeared less restrictive.

In reporting that there had been more than twice as many fire deaths last year as in 1975, fire officials noted that there have been sharp fluctuations over recent months and years in the death toll.

They noted that there have already been four fire-related deaths here so far this year.

Chief Flaherty said careless smoking appeared to have been a principal cause of last year's deaths.

In addition to warning against this, he said, the department's new educational program also would try to emphasize the importance of such measures as keeping matches from small children, closing doors to prevent fire from spreading, and of having a home escape plan.

As a major safety step. Chief Johnson said he has asked the mayor to initiate legislation requiring smoke detectors in all houses here.

Meanwhile, two fires Thursday night and yesterday caused a total of $80,000 damage, officials said. No injuries were reported.

A two-alarm fire caused $40,000 damage about 12:30 p.m. yesterday to a house at 402 9th St. NE, where Mack Williams, the occupant, had been trying to repair a basement hot water heater, fire officials said. They said he left the house to get tools, and when he returned there was an explosion, which touched off the fire.

About 7 p.m. Thursday, officials said, fire caused about $40,000 damage at the home of Carl Wright at 2401 Wagner St. SE. Fire officials said that they believed the fire was set with flammable liquids, and that it is under investigation.