CPD Training Course

Members of the 48.3 Scaffold Design team recently attended a CPD (Continual Professional Development) day held by the Scaffolding Association in Birmingham. The course was delivered by Eur Ing Peter F Pallett, BSc, CEng, FICE, FCS and covered a range of topics related to scaffolding design.

The course provided a great 'refresher' on certain items that designers can lose focus on if they do not come across them in their line of work for a while. Below is a selection of points which we found interesting which were discussed by the group during the day along with some notable updates:

1. The NASC re-issued TG9 in March of this year (becoming TG9:12) A Guide to the design and construction of temporary roofs and buildings which replaces the previous issue from September 2010.
2. The HSE document SIM 02/2010/04 'The Management of Temporary Works in the Construction industry' is a guide for HSE inspectors on how they should enforce this topic i.e. the guidelines on whether they should issue a prohibition notice for non-compliance or not! It is available on the HSE website: HERE
3. Clarification on the legal orientation of the CDM regulations. In the UK typically you are 'innocent until proven guilty'. When applying the CDM regulations the onus of proof is on the individual so you could say you are 'guilty until you prove yourself innocent'. Therefore it would be up to the individual to prove to the court that they are operating to current industry best practice. In practical terms, the best way to ensure you are doing this as a temporary works or scaffolding designer is to follow the guidance provided by BS 5975:2008+A1:2011 and keep records for each project that you have done so.
4. Confirmation that Ready-lok transoms are proprietary items and are not covered by TG20. The supplier of the item has a legal responsibility to provide safe systems of use. The methods of work from TG20 can be applied to scaffolds constructed from Ready-lok transoms, but the safe height tables can not. However after a recent NASC technical committee meeting, it has come to light that CADS will be completing analysis of the Ready-lok unit with a view to including standard design solutions in TG20:13.
5. The consideration in design of elastic shortening of steel and aluminium supporting structures under load i.e. falsework shoring for concrete or any kind of dead shore where new permanent works are being installed. BS 5975 cl.19.3.1 (b) gives typical values of  elastic shortening of "0.5mm/m for steel and 0.9mm/m for aluminium. Joints in components will take up under load, an allowance of 0.5mm per joint and of 1.0mm wherever the member receiving load is timber".
6. The load bearing capacity of an independent scaffold is dependant upon the buckling length of the inside standard parallel to the facade of the building (TG20 analysis method). There are three main ways to provide lateral restraint to the nodes points on the inside standard so that the effective length of the inside standard can be taken as the lift height. These are: 1. Fix face bracing to the inside row of standards to the same parameters as those given for fixing to the outside standards. 2. Fix plan bracing between the inside and outside standards on the 'face braced' bays of the outer standards. 3. Tie the scaffold using a tie pattern that provides a tie on every lift (typical diamond arrangement) and select a tie and tie mechanism that is capable of resisting a horizontal load parallel to the building face (typically known in the industry as a 'shear tie').
7. Class 'B' edge protection systems (BS EN 13374) can not be built out of traditional tube and fitting materials. Tube and fittings can be used for class 'A' only.
8. When sheeting a temporary roof, the side supporting scaffold should always be sheeted first before any sheeting is fixed to the roof. The difference in force coefficient for an enclosed building vs an open sided canopy is three, and it is unlikely the design would consider this if the final scheme is to be fully sheeted.