This note relates to England and Wales
1 Introduction
1.1 Demonstration of compliance with Part A of the Building Regulations is an important safeguard against an inadequate margin of safety. This is a legal requirement that is usually discharged through compliance with the 'deemed to satisfy' codes of practice scheduled in Approved Document A.
1.2 Good practice would suggest that the submission made to Building Control is to a professional standard (regardless of whom actually makes the submission) reflecting the safety-critical nature of the submission, the technical complexity, and the legal obligation. This infers that the submission should:
- clearly set out the key assumptions so that those assessing it may understand the approach taken.
- be co-ordinated
- be checked
Unfortunately, these basic requirements are frequently not achieved and there is no formal guidance on the matter.
This discussion note sets out what are considered to be:
- the essential standards and
- points of information that should be given at the beginning of the submission/calculations.
2 Background
2.1 Despite the fact that structural engineering is safety-critical (and formally recognised by HSE as such), there are no pre-requisites placed on those who choose to make submissions. The introduction to BS5950 (steelwork design code) states:
It has been assumed in the drafting of this British Standard that the execution of its provisions is entrusted to appropriately qualified and experienced people and that construction and supervision should be carried out by capable and experienced organisations.
Similar expectations apply to other material design codes of practice.
2.2 The use of standard details from Part A may signal to some that no specific expertise is required.
2.3 Those 'designers' who are submitting designs in furtherance of a business activity, have legal responsibilities under the Health and Safety at Work Act and in particular, the CDM Regulations, no matter what the size of project. They also have a duty of care under civil law. Unfortunately, those 'designers' who are not part of a business, typically general householders, have no responsibilities under HSWA.
Notwithstanding, existing legislation is a blunt tool in terms of ensuring standards are attained.
2.4 The process of determining compliance with the Building Regulations by local authorities has been significantly affected by a combination of:
- the obligation to recover their costs in discharging these duties, often leading to severe constraints on input,
- a lack of suitably competent staff,
- the influence of Approved Inspectors
2.5 This situation needs to be viewed against the effect of commercial pressures on industry, skill shortages and the introduction of new codes of practice in respect of the maintenance of standards.
2.6 There is strong anecdotal and direct evidence to suggest that the current situation is undermining the importance of structural engineering to the health, safety and welfare of those in and around buildings, and is creating a situation where there is an 'accident waiting to happen'.
3 Essential competence standards
Individuals
3.1 Part A is concerned with structural safety. The analysis, design and checking of structures to ensure structural safety requires competent input. There are examples where even the simplest of 'designs'-even using standard details- can lead to problems if the wider implications are not understood.
3.2 Ideally those undertaking this role should be members of an appropriate professional institution e.g. IStructE or ICE. Alternatively, they should be able to demonstrate appropriate competence in respect of education, training and experience.
3.3 In most cases it is not appropriate for someone without this background to be involved, regardless of the scale of the work.
Submissions
3.4 Submissions should be presented in an acceptable format i.e. one that allows ready assessment of the technical detail, methods used, software adopted.
3.5 Those originating submissions should not rely on the building control approval process as a primary check on their work. Anyone undertaking structural design has an obligation to satisfy themselves that it meets accepted standards and that they have exercised due skill and care.
3.6 All submissions should:
- Justify structures as structurally stable and complete (even if further elements of the project are yet to be submitted). A check cannot be undertaken on an incomplete structure.
- Include sufficient quantities of co-ordinated drawings and details to allow a proper understanding of the submission,
- Explicitly identify the party responsible for each element of design, and for overall stability.
4 Essential information
4.1 In order that submissions may be adequately assessed, it is suggested that all submissions should schedule the answers to the following technical questions on a frontispiece to the calculations:
| |
Category & subject |
Concern & comment |
| 1 |
Is the submission made on a 'deemed to satisfy' basis ? |
If only in part, describe the boundary. |
| 2 |
If yes to Q1, list the structural design codes with which it complies: |
This is particularly important as we will be entering an era when Eurocodes will be used alongside existing codes. |
| 2a |
If Yes to Q1, and the submission utilises standard details from Approved Document A, confirm that the structure satisfies any limitations on the use of these details. |
|
| 2b |
If no to Q1, explain the basis of design |
This requires sufficient detail to allow others to understand the structural principles used. |
| 3 |
Into what class has the structure been placed for purposes of disproportionate collapse design (Table 11 of AD-A) |
If the structure is in a number of classes describe the division. |
| 3a |
Describe:
i) how the class has been arrived at, and |
i) This is particularly important with existing structures which are subject to a material change. |
|
ii) the measures taken to guard against progressive collapse. |
ii) The Approved Document allows a number of structural options. |
| 4 |
Describe (illustrating as required to give sufficient clarity) the load-path to the foundations and how lateral stability is achieved. |
This should deal with both the final and key interim construction stages. |
| 5 |
Confirm that:
i) the structure may be safely built and, |
i) A requirement of the CDM Regulations |
|
ii) that suitable information in this regard will be made available to the contractor. |
ii) In all but simple cases this should include a description/diagram of the assumed construction sequence of the key members, illustrating any issues relating to interim stability (see Q4). |
| 6 |
Name the organisation, or individual, which has overall responsibility for the stability of the structure as required by BS 8110, 5950, 6828 as appropriate. |
See Clause 1.02 (BS5950); Foreword (BS8110), Clause 1 (BS5628) and Clause 1.3 (EN 1990). |
| 7 |
Schedule the software used, and for what purpose; confirm that its application and limitations are understood and that the results have been verified. |
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Software
4.2 The ubiquitous use of software has made the review process difficult. Many submissions are made with an abundance of output but without any explanation as to assumptions, limitations, defaults and the like. Software is often misused.
5 Conclusions and Recommendations
5.1 The Building Regulations approval process should be as simple and open as possible, consistent with safeguarding the health, safety and welfare of those in and around buildings. However it also needs to recognise that:
- structural engineering is safety-critical
- submissions must be made by competent persons
- submissions need to make clear the fundamental assumptions on which they are formulated.
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