Scottish Water: Updated technical specifications now available

Both documents were previously updated in August 2015 and have now undergone a review to take into account changes to technical standards applied across the UK water industry and to provide improved clarity on Scottish Water’s requirements in terms of specification for the design, construction and vesting of new water and waste water infrastructure assets.

Some of these updates are:

Sewers for Scotland

• SUDS Update - Detailed design guidance and standard details to allow the design and construction of vestable end-of-pipe Swale and Filter trenches.
• Vestable Sewer Sizes and Materials - Clarification on the materials and max diameter of vestable sewers has been added where there was no guidance previously.
• Design Peak flow – An increased peak flow rate from individual properties, 4000 to 4300 litres/unit/day to harmonise design flows with DIAs, to allow for cross-connections and infiltration.

Water for Scotland

• Electrofusion Jointing - The use of EF jointing is now being allowed when supported by smart box technology with the records and weld data available for interrogation. The process (App P) details SW’s requirements in compliance with WIS 4-32-08 and the use of a photographic record for audit purposes.
• Location of Water Mains – The option to construct mains on the opposite footpath to avoid congested services and to allow clear future access.
• Fire Mains – The design and construction to be in conjunction with this specification.
• Clarification Appendices - A number of appendices have been added and referenced in the document that help clarify SW requirements:
  • App L – Connection Overview (DRAFT).
  • App M – Barrier Pipe Requirements – an existing SW document added to provide clarity.
  • App N –  Water Main Protection Policy – an SW existing document added to enhance its availability.
  • App O – New guidance on the correct use of Marker, Tracker and Fire Main tape (TBC).
  • App P – New EF jointing procedure.
  • App Q – New guidance on Pre-Start meeting requirements (TBC).
  • App R – Pressure Testing Requirements (TBC).

A full list of revisions is contained within the ‘Record of Changes and Amendments’ table at the beginning of each document.

You will note that a number of the Appendices in WfS are marked as “Draft” or “TBC”. The supporting processes and procedures are currently being finalised within Scottish Water. These will be completed and the appendices available on the Scottish Water website from 1st December 2018.

The updated specifications are now available on the Scottish Water website: https://www.scottishwater.co.uk/you-and-your-home/connecting-your-property/planning-your-development

All new designs submitted in relation to development in Scotland, that previously applied WfS3 and SfS3, will now need to comply with WfS v4.0 and SfS v4.0 as of 1st January 2019.

With regard to future updates, Scottish Water advise that WfSv4.1 and SfSv4.1will be released in June/July 2019 with some minor alterations and updates. A major update of both documents is expected in early 2020, that will see full stakeholder engagement and a release of v5.0.

If you have any immediate queries regarding these documents, please send them to the Standards.InfoLine@scottishwater.co.uk mailbox.