“From what I understand in modern systems, if critical components of sprinkle systems are shut off such as pumps or main valves it triggers a “trouble” alarm in the fire panel. it will not sound the alarm and cause a evacuation, but the alarm company will get a alert that something is wrong”
You are correct. This building, however was built in the 70s, originally. Given the renovations though, it should have been brought up to current standards. The US has no waivers for full renovations, no “grandfathering”. That would mean that if there weren’t sprinkler systems originally, there would be now. I can say, it’s very clear to me that there either were NO sprinklers, or something caused them to fail at the ground floors. You’re mention of a pump is spot on. general water pressure would not make it anywhere near the top floors if that pump isn’t operating and yes, the building manager would have gotten a trouble signal (probably repeatedly) about the problem. Those pumps are tested annually, also. The fact that witnesses are universally saying there was no alarm is a good indicator that either the system was completely broken, or there wasn’t a system.
From a deliberate (terrorist) standpoint, someone could have simply shut of the building main fire riser, and deliberately set the fire. I doubt this, as they are typically locked in the open position, and the perpetrator would have to know that would send a “supervisory” signal to the building manager, at least by phone. At that hour, it’s possible he/she would sleep through the call, but if your me, you pick up all monitoring calls or call back immediately if you miss it. I have responsibility of 22 buildings, office and retail. Generally, mine are unoccupied after 9pm. Residential is quite different, lives are at stake. In any case, there was an enormous breakdown somewhere. This fire never should have gotten so out of control.
Unless, of course, the arsonist(s) disconnected the sprinklers off alarm.