Currently, sprinklers are mandatory in new school buildings in Scotland and Wales, but not in England and Northern Ireland - and the National Fire Chiefs Council says that must change.
London Fire Brigade Commissioner Dany Cotton accused the government of "playing with children's lives".
The Department for Education said the safety of children was their priority.
Fire safety in public buildings like schools has come under close scrutiny since the Grenfell Tower fire in west London in June.
There are about 700 school fires a year in England.
Last year, the DfE in England began a consultation on new draft guidance which said building regulations no longer required "the installation of fire sprinkler suppression systems in school buildings for life safety".
"Therefore," it added, "[guidelines] no longer include an expectation that most new school buildings will be fitted with them."
Ms Cotton told BBC Breakfast she was appalled when she saw that draft guidance.
"I think it was outrageous," she said. "I thought, 'How can we play with children's lives like that?'
"I just do not understand why it wouldn't be made compulsory and wouldn't be made a requirement to fit sprinklers in schools at new-build stage.
"And what I don't want to see is a very large school fire to be the thing that brings about that change."
The consultation was dropped after Grenfell so the guidance was never changed.
Less than a third of the 260 schools built since 2014 under the Schools Building Programme have sprinklers.
The DfE says all schools must have a Fire Risk Assessment and new schools undergo an additional safety check while being designed.
"It has always been the case that where the risk assessment recommends sprinklers in a school building, they must be installed," a spokesman added.
The Local Government Association said it "fully supports the installation of sprinklers in new school buildings as a cost-effective measure which can help save lives, protect property and improve firefighter safety".
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