Would you buy a car that had not been tested as an integrated whole? Would you accept a new car with a small defects list called the 1 year defects period? Of course not. Then why is it seemingly OK to hand over buildings without integrated testing and large defect lists?
I have never meet a building owner who has said “I am OK with a defects list and no proof my building works”. IMHO you get what you are willing to accept.
Why are building systems frequently not tested as integrated wholes?
There are many reasons, some of them cultural. IMHO some of the biggest reasons are:
- Design and construction contractual responsibilities are delineated into “silos”.
- A lack of understanding of the complexity and interactions between building systems. The building should be considered as a single system incorporating subsystems within.
- Owners willingness to accept untested buildings with defects.
How can you deliver buildings that actually work? The answer is specifying “Global Integration Testing” (GIT). Testing components, equipment and then systems as integrated wholes, including verification of their designed interactions.
GIT “begins with the end in mind”, it is outcome based. The level of GIT is dependent on building size and complexity.
The following distinct hierarchy of testing and validation needs to take place to ensure that the completed building is reliable in operation and resilient in part and full failure.
Level I – Component Testing
Verification of device and component functions, and is the lowest level of testing. It can be summarised as the tests that can be conducted without power i.e. BMS point-to point testing, pipework pressure testing, ductwork pressure testing. This also includes the Factory Acceptance Testing of mission critical equipment to ensure conformance with specified performance.
Level II – Equipment Start-Up
The individual equipment is brought from a state of static readiness to dynamic operation via the manufacturers approved route of start-up, as well as the initial setting up of the BMS controls system. Unfortunately this is considered Commissioning by some and where testing stops.
Level III – System Interface Testing
This can only begin upon successful completion of Level II testing, and is designed to ensure that each “system” operates as both a single and a holistic entity. Demonstration of the systems can only take place after the completion of this testing.
Level IV – Global Integration Testing (GIT)
This is the highest level of testing and includes integrated testing under all modes of operation via false loads in the space if required (e.g data centres). It is during this phase that the overall resilience of the system and building is checked, and whether the design intent has been met. Level IV testing, verifies the overall facility resilience during agreed operational scenarios. It is during this phase that the integrated cause and effect testing is performed to demonstrate system functionality and redundancy under normal and emergency power is conducted.
The presumption by owners is that they have paid for a fully operational and tested building. GIT is the way to hand over clean, with proof of building functionality. If you are a main contractor, look at GIT as a risk management tool. GIT is a formal test and record of the construction outcome on completion.