Temporary works design check categories: UK, NZ and Australia

Temporary works design check categories set how independent the check of a temporary works design must be. The UK, New Zealand and Australia all use a scale that starts with a check by a colleague and ends with a check by a separate organisation. The UK categories come from the British standard BS 5975, and the Australian guidelines build on them. The three systems differ in what drives the category and who decides it. The UK and New Zealand use Category 0 to Category 3. New Zealand sets the category from a matrix of consequence and complexity. Australia's Temporary Works Forum guidelines split the question into consequence of failure risk (CFR), design complexity risk (DCR) and execution risk (ER), and add a level at each end. By the end of this article you will know how the three systems line up, where they differ, and what to check when you move between them.

The short answer

	United Kingdom	New Zealand	Australia (TWfAU)
Main guidance	BS 5975, described by the UK HSE [1] [2]	TWf NZ TGN 05.23, July 2023 [3]	TWfAU Temporary Works Risk Guidelines, TWfAU2020: 01 [4]
Levels	Category 0 to 3 [1]	Category 0 to 3 [3]	DCR00 and DCR0 to DCR4, with CFR and ER beside them [4]
What sets the level	The nature of the design [1]	A matrix of consequence of failure and design complexity [3]	DCR for complexity, raised where the CFR is high [4]
Who decides	Not stated in the HSE note; set by your procedure	The temporary works coordinator (TWC) [3]	The client, through the design brief [4]
Highest check	Another organisation [1]	Another organisation [3]	A separate organisation, plus a peer review for the highest risks [4]

The rest of this article explains each row.

The UK: BS 5975 Categories 0 to 3

In the UK, the British standard for temporary works procedures is BS 5975. BSI revised it in 2024 and split it into two parts: BS 5975-1:2024 on the management procedures for temporary works, and BS 5975-2:2024 on falsework design [2]. The UK Health and Safety Executive (HSE) points to both parts from its temporary works page [5].

The clearest free description of the check categories is in an HSE guidance note for its inspectors, SIM 02/2010/04, written against the 2008 edition [1]. HSE says the note is due for revision after the standard, but that its content remains valid [1]. Check the current edition of BS 5975-1 for any change. In the note's terms, paraphrased:

Category	What it covers	Who checks
0	Standard solutions only; the check confirms the site falls within the solution's limits	Another member of the site or design team
1	Simple designs using simple analysis, such as basic formwork, falsework without assumed top restraint, and propping to openings in single storey brickwork	Another member of the design team
2	More complex designs, such as excavations, foundations, steelwork connections and reinforced concrete, often needing interpretation of loading or ground information	Someone not involved in the design and not consulted by the designer
3	Complex or innovative designs, such as complex sequences, unusual designs, departures from standards or new methods of analysis	Another organisation

Two points stand out. Category 0 still relies on the standard solution having had its own Category 1, 2 or 3 check when it was designed [1]. And in the note the category follows the kind of design, rather than what is around it [1]. The note also makes the temporary works coordinator (TWC), the person who makes sure the contractor's temporary works procedure is followed on site, responsible for seeing that the designer and checker get an adequate brief [1].

New Zealand: a matrix of consequence and complexity

New Zealand's Temporary Works Forum (TWf NZ) published Technical Guidance Note 05.23, Temporary Works Risk Assessment and Categorisation, in July 2023 [3]. It supplements the forum's Temporary Works Procedural Control Good Practice Guideline, GPG01:19 [3].

The note keeps Categories 0 to 3 but sets them from two ratings [3]:

Consequence of failure, in four levels from Minor to Catastrophic. It is based mainly on safety, but an environmental, commercial, programme, reputational or social consequence can take over if it is more severe.
Design complexity, in four levels from Basic to Complex or Innovative, with examples for each. Scale, constraints, the loads and site factors can move an item up or down.

A matrix combines the two into the check category [3]. The effect is that an ordinary design next to something that matters can land in a higher category than its complexity alone would give.

The note is firm about responsibility. The TWC has the final say on the category and should record the reasons for the ratings [3]. Talking it through with the designer is encouraged, but does not move that responsibility [3]. Where the matrix gives a result that seems optimistic, the note says to consult someone experienced in temporary works risk assessment [3].

New Zealand also ties competency to the category. For Category 2 the checker must hold CPEng, the professional engineering title used in New Zealand, and for Category 3 both the designer and the checker should hold it, with the check done by another organisation [3]. A more onerous requirement, such as a client's specification, takes precedence [3].

Australia: CFR, DCR and ER

In Australia, the published guidance on check categories is the Temporary Works Risk Guidelines of the Temporary Works Forum Australia (TWfAU), a community of practice within Engineers Australia. The guidelines are an Australian adaptation of the UK Temporary Works Forum's clients' guide [4]. The forum describes them as a first draft for comment [6].

The guidelines separate three questions [4]:

CFR, consequence of failure risk: how bad a failure would be, CFR0 to CFR3.
DCR, design complexity risk: how complex the design is, DCR00 and DCR0 to DCR4.
ER, execution risk: how likely a failure is through workmanship, use or removal, ER0 to ER3.

The DCR is the check category. The guidelines say BS 5975 handles design complexity through its four checking categories, which they adopt and extend at both ends [4]:

TWfAU	Closest UK category	Who checks
DCR00	None	The site's method statement approval process, with no design
DCR0	Category 0	Another member of the site or design team
DCR1	Category 1	Another member of the design team
DCR2	Category 2	Someone not involved in the design and not consulted by the designer
DCR3	Category 3	A separate organisation not involved in the design
DCR4	None	A separate organisation not involved in the design

DCR00 covers items a competent site team manages without a design, such as kicker shutters, and only where the CFR is low [4]. DCR4 covers exceptional, highly innovative designs and any scheme with CFR3 [4].

Consequence comes in through the CFR. Where the CFR is CFR2 or CFR3, the guidelines expect the DCR to be raised [4]. For any scheme at CFR3, DCR4 or ER3, they say a peer review is appropriate on top of the check [4]. For more on each category, see temporary works risk categories: CFR, DCR and ER explained.

At least one Australian contract specification has adopted the system. The South Australian Department for Infrastructure and Transport's specification PC-CN4 requires temporary works to follow the Engineers Australia guidelines and the contractor's design management plan to say how each CFR, DCR and ER is set [7].

Where the three systems differ

What drives the category. In the UK note, the category follows the kind of design [1]. In New Zealand, consequence and complexity are combined in one matrix [3]. In Australia, they stay as separate ratings, and a high CFR pushes the DCR up [4].

Who decides. New Zealand gives the decision to the TWC, with the reasons recorded [3]. The Australian guidelines put the categories with the client in the design brief, and the designer can ask for more information [4]. On an Australian project, the client is often the contractor: the SA specification reads the guidelines' client obligations as the contractor's [7].

The ends of the scale. Only Australia has a level below Category 0 (DCR00, no design) and above Category 3 (DCR4) [4].

Execution. Only Australia rates the risk on site as its own category, ER, with the designer stating the controls and hold points to manage it [4].

Competency. New Zealand links the check categories to CPEng [3]. The UK note deals with the TWC's competence, putting relevant experience first, then training, then qualifications [1]. Check what your contract and jurisdiction require of the designer and checker.

A checklist when you move between systems

Find which system your contract uses. A specification may call up the TWfAU guidelines, BS 5975 or a client procedure. Where they differ, the contract and the more onerous requirement govern.
Translate the category, not just the number. A UK Category 2 design beside a railway may be a DCR3 or DCR4 in Australia once the CFR is considered.
Check who must decide. Know whether your TWC, your client or your procedure owns the category, and record the reasons.
Check the checker's independence and competency. Confirm the checker meets the level for the category, and any qualification your jurisdiction or contract requires.
Plan for the extra steps. In Australia, allow for a peer review at CFR3, DCR4 or ER3, and for the designer's ER controls and hold points.
State it in the brief. The proposed category and the reasons belong in the design brief, so the designer and checker can challenge them before design starts. See how to prepare a temporary works design brief.

TworkX proposes the CFR, DCR, ER and the check category from the brief's data, each with its reasons, for the author to decide. How it works shows where.