That is because sprinklers were only recommended, but not incorporated into building regulations for such structures as of the time it was built.
I have done a case study in the operations of airports and also had to demonstrate I understood how building project management works, as part of my chartered qualification.
I have also undertaken fire risk assessment as part of another project. The risk management report I compiled had to go to the senior partner of the top 50 city firm of accountants, where I was working, as part of fulfilling vocational qualification requirements. I heard nothing back from him, but within days, all of the problems I had reported were suddenly acted upon (for example, there was an entrance to the building that was locked up and unused, with regular great piles of spam mail on the doormat: within days, the letter box was sealed off accordingly, with alacrity, acting on my recommendation; possibly because our previous offices in Bishopsgate had been bombed by the IRA in previous years [before my time]).
OK, so this is white-collar managerial stuff but it still requires an in-depth knowledge of industry, even if one never had to put on a hard hat.