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Navigation & Caveats


WIS and IGN are displayed in descending order of their date of publication – most recent first. Checking the appropriate boxes will filter the list based on the search criteria specified.

Where a document has seen successive ‘Issues’ a specific WIS or IGN will have its Issue Numbers listed in descending date of publication – most recent first. All but the latest Issue will be shown as ‘Archived’. Where there are gaps in the order this is because the Board currently lacks a copy of that Issue.

Current Standards

A document’s contents are only truly ‘current’ at the time of publication. Many rely on extensive referencing to the latest versions of other documents (e.g. BS or BS EN standards). However as the latter change their influence on the WIS or IGN may produce inconsistencies in interpretation.

Many of the WIS or IGN still listed as ‘current’ were written over 20 years ago and have not been revisited since.  In 2021 the Standards Board initiated a review to assess whether 27 of the oldest documents could continue to be described as ‘current’.  The output from  that review was endorsed by the Standards Board in Spring 2023. The review concluded that, whilst 11 of the documents should be archived, the remaining 16 had continuing value but required updating.

To better describe the status of this latter group an additional category of ‘ageing’ has been introduced. A summary of the review’s conclusions can be found here WIS & IGN Review Project Outputs Spring 2023 v1 300623 and work to recategorize these documents is in hand.

It is for you to determine the extent to which the document retains value in the face of changes since its publication. Your attention is directed to the three descriptions of ‘caveats’ below and any specific caveats relating to an individual WIS or IGN. These caveats may not yet include conclusions from the Review’s findings. However, they may assist you in forming a view on a specific document’s continued relevance to your needs. Use of a ‘current’ or ‘ageing’ WIS or IGN today is entirely at your own risk.

Ageing Standards

These are standards that the Board has determined should no longer be described as ‘current’ due to the length of time since their publication and the absence of any subsequent detailed technical review. A two-year review project, that concluded in Spring 2023, examined 27 of the oldest WIS & IGN. Of these 16 were found to have been subject to external changes (e.g. due to publication or updating of national, European or international standards being referenced; or product or industry innovation) that rendered them no longer fully current. However, the documents were considered to retain sufficient value that they might, with careful interpretation by users, still have some residual value.

Archived Standards

These are standards that the Board has determined should be withdrawn as no longer current. This can be for a number of reasons. For example: a later Issue may exist; the material, product or process may no longer have regulatory approval in the UK; or the material, product or process may (for practical purposes) no longer be widely used.

A primary reason for maintaining archived standards is to assist those involved in assessing the condition and serviceability of existing assets that were specified, manufactured, procured, designed and/or constructed at the time the standard was current. Another reason is to support asset failure investigation.

Draft Standards

New WIS or IGN continue to be published under the process described in IGN 4-00-02. ‘Almost final’ drafts are displayed on this site for public comment for 3-months prior to finalisation. Those listed as ‘draft’ are at that stage.

Caveats to a Standard

Investigations by the Board on a specific WIS or IGN’s continued currency frequently reveal circumstances (e.g. events, amendments, changes) warranting users’ awareness. Such circumstances may influence users’ own views on that document’s currency or interpretation. Interpretation of these caveats is entirely at your own risk.

Important Caveats

Important caveats, unique to a specific document, will be presented when you have selected the document you are interested in, but before you are invited to download it. For example: for a current WIS the caveat might draw attention to advances in materials or plant not yet included in the document; for a withdrawn WIS the caveat might refer to its replacement by a specific BS.

Common Editorial Caveats

A number of caveats are so common that their repetition on individual documents might result in more important ones being missed. The following are common caveats. You should check to see if they apply to the document you are interested in.

  • Some embedded links are no longer active.
  • The document is uncontrolled once printed but lacks a watermark to that effect.
  • Water UK’s address and/or contact details have changed.
  • The WRc email address for technical queries is no longer operative.
  • The document was reprinted for web publication in June 2006.