The level of checking required for temporary works designs is clearly defined under BS5975.
The checking of temporary works is split into four categories under BS5975 from CAT 0 through to CAT 3. The correct checking category for a temporary works design is defined by the complexity and scope of a project, this also determines who can perform the check.
The more complex the project the more scrutiny is required and the more organisational distance is required between the original designer and the checker.
Temporary works should be checked for
- Design concept
- Strength and structural adequacy (including foundations and lateral stability)
- Compliance with the design brief
CAT 0 Check
This design category only applies to standard solutions and not original designs
Who can carry out the check – Another member of the site or design team.
CAT 1 Check
This check is for fairly simple designs and can include formwork, brickwork, falsework; needling and propping. There should be a formal design undertaken and the checker will go through the design and calculations and sign to say they agree with what has been designed.
Who can carry out the check – Another member of the design team.
CAT 2 Check
This check is for more complex or involved designs than those suitable for a CAT 1 check.
This includes designs where loadings or soils information needs to be interpreted as part of the design.
The checker is issued with the design brief, the design methodology and the drawings. They are not issued with the calculations. The checker will do their own independent calculations meaning that during the check two sets of calculations will be issued.
Who can carry out the check: Someone not involved in the initial design, at Andun we aim to send them to a different office.
CAT 3 Check
A CAT 3 check is the highest level of check that is required for novel methods of analysis or where considerable exercise of engineering judgement is required.
This check is for complex or innovative designs, which result in complex sequences of moving and/or construction of either temporary works or permanent works.
A CAT 3 check is always required for basement excavations and tunnels.
As per CAT 2 checks, the checker is issued with the design brief, the design methodology and the drawings. They are not issued with the calculations. The checker will do their own independent calculations.
Who can carry out the check: Someone from a different organisation than the designer
What To Expect From Cat 2 & Cat 3 Checks
During our Checking Temporary Works Webinar on the 29th of July, here is what you should expect during a CAT 2 & Cat 3 Check.
Access our Temporary Works Procedures Flowchart