There is no single thing called a fire alarm certificate. There are design, installation, commissioning and verification certificates for a new system, and there are service and inspection reports for an existing one. They prove different things and a building that has only the last of them cannot demonstrate that the system was ever right in the first place.
The four certificates for a new system
Design says what category and grade the system was specified to and who decided it. Installation says the equipment was installed to that design. Commissioning says the installed system was tested and works as designed. Verification, where it is provided, is an independent check of all three. Together they are the evidence that the system on your wall is the system somebody designed for your building.
Service and inspection reports
Once the system is in use, each periodic visit produces a report saying what was tested, what passed, what failed and what remains outstanding. This is the document most people mean when they ask for a fire alarm certificate, and it is the one an enforcing officer will read alongside the log book. A report with no outstanding items over several years is unusual enough to be worth questioning.
What the certificate does not do
None of these documents makes you compliant. They are evidence that supports the fire risk assessment, which is where compliance actually lives. A perfectly executed service report on a system of the wrong category for the building's current use proves that the wrong system is working properly, and that is a finding rather than a defence.
What to keep and for how long
Keep the original design, installation and commissioning certificates for the life of the system, because they are irreplaceable and they define what the maintenance contractor should be testing against. Keep service reports and the log book for long enough to show a pattern, which in practice means several years. Store them somewhere other than the cupboard next to the panel.
Questions people ask about fire alarm certificate
Is a fire alarm certificate a legal requirement?
The law requires the system to be maintained in efficient working order and the risk assessment to be recorded where the thresholds apply. Certificates are how you evidence that, rather than a duty in themselves.
Who can issue a fire alarm certificate?
A competent person or firm, with third party certification schemes existing precisely so that competence can be checked independently. Check the scope of the certification covers the activity being certified.
My contractor issued a certificate with faults outstanding. Is that valid?
It can be, provided the outstanding items are listed clearly and the responsible person is told. What is not acceptable is a clean certificate on a system with known defects.