One of the prime objectives of the revision to one of the most important sections of the code, Description of soils and rocks, was to make it more user friendly, especially for site staff.
For this reason, the description reference table has been reorganised so that is now in the order that descriptions are written and has been joined by a flow chart that summarises the descriptive process.
Soils are now described on the basis of fine or coarse grained, because of confusion over the terms 'cohesive'and 'non-cohesive'(or granular), as soils placed in either category can exhibit behaviour of the other (see 'What BS5930 says about the c-word').
Another criticism of the 1981 code was the rock weathering classification, based primarily on chemical weathering processes rarely experienced in the UK.This time round, the code admits that 'the best method of classification of rock weathering is a continuing subject for debate.'
It says the main requirement is to give a full factual description of the degree, extent and nature of weathering.
A flow chart with a variety of approaches, including broad classification schemes, is given although 'subsequent formal classification may be inappropriate; indeed although it is useful, it should only be applied where both well established and sufficient information is available in order to make an unambiguous classification.'