I have been asked by people on our first intermediate scaffolder course under 30497QLD to explain why the WHSQ assessment is misleading. So although it is an involved topic I will try my best.
(1) The written assignment states that cantilevered putlogs have to be connected using right angle couplers. As any practical person who has attempted this knows one of three things happens -(a) the planks are unable to sit flat because of the bolt on the coupler protruding above the centre of the ledger/putlog connection; (b) if the boards are kept inside the coupler then a gap of approximately 100 mm appears between the normally supported boards and the boards supported by the cantilevered part of the putlogs; and (c) if you try to connect the putlogs to the standards (which you shouldn't do anyway) there is a height difference between the putlogs at the standards and those connected in between. So where does this foolishness come from? Well unfortunately it comes from AS/NZS 1576.6. Before the new WHSQ assessments were adopted, assessors throughout Australia were able to use the old assessments which were based on Supplement 1 to AS 1576.3. In States other than Queensland this still applies, thankfully. Unfortunately in Queensland we are no longer able to do this as the new assessment instrument seeks to comply with AS/NZS 1576.6. In doing so WHSQ have made some unfortunate decisions - decisions which advocate the construction of unsafe scaffolds. It is not necessarily their fault BUT it is a shame that a body that administered the Scaffolding Act should be unable to arrive at better solutions. After all, the new National Draft Standard for Intermediate Scaffolder assessment has managed to do so.
(2) The only way to overcome the problem of compliance with AS/NZS 1576.6 and build a safe scaffold is to use transoms at the intersection of all ledger to standard node points. This is not necessarily a bad thing as it uses little extra tube (because you no longer need to put two putlogs on either side of the standards) and also stiffens the scaffold in the transverse plane to a greater extent than before.
(3) BUT WAIT, THERE'S MORE! Tables 1, 3 and 4 of AS/NZS 1576.6 further confuse the issue with respect to the size of bays permitted. Briefly they no longer provide maximum bay lengths and the typical bay sizes are contrary to what was in the previous "Deemed to comply" Supplement 1 to AS 1576.3 and what is contained in other Australian/New Zealand standards. For example the typical maximum length of a heavy duty bay would appear to be 2.4 m whereas the typical maximum length of a light duty bay is given as 1.5 m. This defies common sense: why have smaller spacing and hence greater load carrying capacity for light duty and greater spacing and hence less load carrying capacity for a heavy duty scaffold?????
(4) Then there is the issue of a base lift. Now scaffolders understand that a base lift is a lift constructed at the base of the scaffold - usually in modular scaffolds that need extra rigidity because the method of connection is not as rigid as that provided by use of 90 degree (double) couplers. But there is no definition of, nor succinct instruction, as to when to use a base lift for tube and coupler scaffold - only a vague note to Section 3.2.1 on Ledgers, saying that they should be considered for "high scaffolding, scaffolding erected on sloping ground, and scaffolding erected on a low-resistance surface."
(5) The problem is twofold: the major one is the drafting of AS/NZS 1576.6 and until that document is reviewed this unsatisfactory situation is likely to continue; and secondly, loss of credibility by Workplace Health and Safety, Queensland. The assessment developed for Intermediate Scaffolding by Workplace Health and Safety, Queensland shows what can happen when appropriate knowledge and experience is no longer valued within an organisation.
Geoff Manthorpe