Troops in combat uniform put out blazes in nursery schools, washing machines and mattresses today, as Britain made it through the first day of its unprecedented firemen 's strike without a diaster.

The vast majority of the nation's 32,000 fire fighters left their station houses at nine this morning and set up picket lines to prevent any use of the equipment inside.

But 10,000 soldiers and airmen manning ancient "Green Goddes" engines, appeared to be coping with the extraodinary emergency. They were backed up by 13,000 part-time firemen mostly non-union, and a scattering of regular firemen who defied their union's walkout call.

Most towns and counties reported alarms and fewer fires than usual during daylight hours. This suggested that Briton were taking special pains against starting starting fires and were tackling small blazes on their own with buckets of water and garden hoses.

Britons pride themselves on performing well in crises. During the coal strike four years ago, industrial output barely fell although factories were limited to three days of power a week.

prime Minister James Calaghan and his Cabinet, it was learned, regard their firm stand against the firemen's demands for a 32 per cent pay increase as the most important event of their 1 1/2-year-old administration. At stake is the government's anti-inflation target of limiting pay increases to 10 per cent. Defeat of the firemen, the government believes, will induce most other union to fall in line.

The fireman make $118 for a 48-hour week. They make about $155.70 for 42 hours, and increase of 51 per cent on an hourly basis. The government will concede the hours but wants the pay $140. This amounts to a 26 per cent gain on an hourly basis.

The government is predicting the strike will last for days, which could be a tactic to wear down the strikes' will. Everything could change radically if a fatal catastrophe occurs.

The greatest potential for diaster is in Northern Ireland, where the IRA has long been tossing firebombs. All the firemen there have gone out, including some part-timers on hardline Protestants towns like Larne. Yesterday, the IRA set off-five incendiaries.

In london, the Westminister station set the striking firemen's pace. Everyman walked out and a picket line was promptly set up. This left the queen amd MPs and lords in Parliament depending on the troops.

For 3 1/2 hours this morning, the soldiers sat around impatiently waiting for a test. Their first was small fire in a garbage chute.

Later in the day, troops were called to east London to tackle a similar balze at a housing development. To their surprise, regular firemen ignored their union and pitched in. Appropriately, the development was the Samuel Pepys estate, which is named for the notable diarist and civil servant who refused to leave London during the week-long Great Firee of 1666.

In Birmingham, two marines battling a blaze in a mattress were over-comed by smoke. They recovered quickly and helped put the fire out. Delighted children in a nursery school outside Wolverhampton saw soldiers in combat douse a blaze started by a short circuit. The youngsters were back at the desks in 15 minutes.

In one village, police put out a fire in a farmhouse before an ait force emergency crew arrived. They rescued an 84-year-old woman who later dies, but it was unclear whether her death could have prevented if there had not been a strike.

The biggest blaze of the day, was a junkyard in the Wet Midlands. Several dozen troops were still manning hoses there as darkness fell.

In one case, strike discipline broke when a fire threatened a pub next door to the fire station in Abingdon. Strikers abandoned their picket line to helpd soldiers put out the blaze.