The emergency service revealed this week that the trust is among the worst offenders in the capital for false alarms in 2014.
The brigade has claimed it was called out to Hillingdon Hospital on 44 occasions last year, ranking it 10th worse in London.
However, Hillingdon Hospitals NHS Foundation Trust says the 44 call-outs covered both Hillingdon and Mount Vernon Hospitals, and that independent leaseholders at the Northwood hospital responsible for some of the false alarms would be footing part of the bill.
Last January, the LFB began recovering £295 for the 10th false alarm attended at the same site within a 12-month period and for all subsequent false alarm call outs.
That means the trust would be billed £10,325. However, the Trust says it is being billed for 19 false call-outs, of which six will be paid by leaseholders, such as hairdressers, charity shop, nursery and dentist, based on its site. This would mean the trust paying £3,385.
Top of the LFB list is St George’s Hospital, in Tooting, with 168 false call outs in 2014, and the rest of the top 10 offenders dominated by hospitals.
The introduction of billing for false alarms has resulted in a 7.3%t drop in cases, but fire chiefs want to see greater improvements.
Neil Orbell, head of fire safety at the LFB, said: “This is not a money-making scheme and the last organisations we want to charge are hospitals. However, we are called to over 30,000 false alarms every year and some hospitals we go to nearly every week.
“We want to work with hospitals on this issue which is why we will wait until the 10th call before we start to recover our costs.
“We also work with them to see how they can improve the maintenance and management of their automatic fire alarm systems.”
A spokeswoman for Hillingdon Hospitals NHS Foundation Trust said: “The trust was issued with 19 invoices - six of these have been passed on to lease holders at Mount Vernon as the call-outs were as a result of their actions.
“We want to eliminate all false-alarm calls and have improved the management of our fire alarm systems to prevent unnecessary costs to our hospitals.”