What is a FAT?

In a recent meeting with a builder and a consultant, we were talking about the early stages of a project’s time line what the term FAT came up between myself and the consultant.

The builder spoke up asking “what is a FAT?”

A FAT stands for a Factory Acceptance Test. A process where you build a mock up of a solution to demonstrate that it meets the functional requirements and identify any problems / oversights in a design.

Typically a FAT will be between the security installer and the consultant but will often also involve the end client to help identify operational processes that may not otherwise become apparent until too late – after the system is installed. 

Factory Acceptance TestWhat makes for a good FAT?

The aim of a factory acceptance test is to demonstrate that the individual pieces of electronic hardware in a system actually work together as one complete system and meet the compliance requirements, typically defined in a tender document.

The key to having your FAT go well is in planning, pre-testing and surrounding yourself with good people, knowledgeable in the key products involved. Sometimes your system will be a standalone component or may depend on other peoples hardware that also requires a level of testing For example the wide area networks or sensing devices such as a fire detection system.

A real example of a FAT I have been involved in involved testing several distinct technologies, all operating over a common wide area network – WAN – to come together as a fully functioning integrated system.

  • Fibre networks
  • RF networks
  • Vehicle detection systems
  • Intelligent signage systems


Plan out your system in advance. Hopefully you did this prior to quoting and winning the project but you should do it again with the input of your knowledge partners as this will highlight potential issues and additional hardware that may be required or could be eliminated due to duplication across systems.


Clearly document what you intend to demonstrate for each component and the procedure you will use to achieve it.

This should include a schematic or block diagram of each of the systems, showing the interconnection and communications between the systems. Where necessary, have a procedure flow chart that shows the sequence of events that need to occur and the expected outcome for each test. As you document the FAT, relate the tests to the requirements of the tender, referencing the clause it relates to. This will help you to know the individual items the assessor is going to want to see and identify any oversights in your design. If you are required to have the FAT pre-approved, this document will be critical to the process and the easier it is to understand how your test demonstrates compliance to each clause of the tender, the more likely that you will be able to proceed to the actual test.

When conducting the test, the documentation will also help you keep on track time wise and give you something to sign off against.

Pre Test

Don’t assume anything and pretest everything. It is much easier to work around a problem that you know about ahead of time. Sometimes things just go wrong but if you have pretested, you know that it did work and should be able to more confidently correct it.

Check your documentation of the proposed tests against your setup to ensure 1. – It does in fact work as expected 2. – You know what you are doing so you don’t fumble around during the assessment.

Knowledge Partners

Having the right people available (not necessarily as employees – just call in your knowledge partners) that know and specialize in each of these systems not only reduces the chance of things going horribly wrong but gives confidence to the assessor that your company has access to the resources that can work to create a solution. The assessors will ask less questions of you appear to understand what you are doing.

 Carrying out the FAT

Now that you have designed, documented and tested everything, you have reached the easy part – getting the sign off.

With the assessor and your knowledge partners, introduce them to each other, explaining their field of expertise and out time the schedule that you are going to follow, including where you plan to have breaks.

  • Have a notepad ready as it is likely you will need to follow up some things.

Now simply go through each step you documented, showing it in operation. Call on your technology partners to do the actual demonstration if you are not confident.

  • Tick of each section as completed or requiring further follow up.
  • As questions arise, identify if a later part of your test will address them or answer them where possible but stick to the documented flow.


Post FAT Sign Off

As you have been going through the FAT, you should be marking off each section as passed or needing follow up. At the end, you will need to ensure the authorized person has formally acknowledged each stage of the test and you agree on the items that require follow up. This is your protection that the system was accepted in the format you have demonstrated it, which means any disagreements that may occur post installation can be referenced back to being accepted.


I hope this has helped you to understand how to work through a factory acceptance test. If you have any feedback or questions, please leave them below.



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