Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/904738
www.wwtonline.co.uk | DECEMBER 2017 | 27 What's new? This new BPF Pipes Group guidance provides quick access to key information for those designing and installing sewer pipework, chambers and manholes. It is divided into • ve clear sections: Drains and Sewer Pipes; Inspection Chambers; Manholes; Covers for Inspection Cham- bers and Manholes; Proving the Integrity of the Wastewater System. In each of the • rst four sections, the correct and current product speci• cations are identi• ed and summarised, terminology is demysti- • ed, and key recommendations given. The • nal section succinctly explains the requirements for whole system integrity testing following construction. BPF Pipes Group members provide detailed support through their technical departments on a day-to-day basis regard- ing the application of Sewers for Adoption and the Building Regulations for drain and sewer construction. Members were well placed therefore to provide expert input to the BSI committee to update the National Annex to EN 752 which now clar- i• es and simpli• es best practice, explains and emphasises the importance of design and product choice on safe working, and supports designers and builders in their choice of products and system layouts. As chair of the BPF Pipes Group work- ing group on drains and sewers, I think that a signi• cant step has been taken by the BSI committee in modernising this na- tional guidance, and the BPF Pipes Group is pleased to have been able to provide the expertise to underpin the work. The BPF Pipes Group is strongly committed to the provision of clear and consistent guidance which is easily acces- sible to developers and designers. Let's now look at the greatest bene• ts of the improvements to clarify best practice. Prioritising safety This has been fundamental to updating the National Annex; everything follows the principles of Con• ned Spaces Regula- tions 1997 for operations to be carried out without entering a con• ned space. This introduces a new challenge to design- ers, to adopt above-ground working as the new default, and having to justify where below-ground working is needed (for example in deep installations and at high maintenance points). This applies even for large diameter public sewers. To help, the new Annex has addressed the confusion over clear opening sizes for access points by explaining the reasoning behind sizing, and by providing consist- ent and easy to follow text which applies equally to private and public systems. Accurate and consistent defi nitions The BPF Pipes Group guidance shows how many di– erent terms are used to describe the same system components. Providing de• nitions which can be used across the industry will minimise con- fusion and save time. For example, the four de• ned access points are: 1. Rodding points: small diameter con- nections at the upstream end of a drain or sewer that permit entry into the system for cleaning or inspection downstream, and which can include gullies incorporat- ing rodding points. 2. Access • ttings: normally located near the upstream end of a drain or sewer, permitting entry into the system for clean- ing or inspection. Restricted access means operations to remove debris using suction hoses are not possible. 3. Inspection chambers: chambers with working space at ground level only, used to introduce equipment for testing, in- spection and maintenance. The chamber's working space normally permits addition- al operations to those carried out through an access • tting, such as debris removal using suction hoses or over-pumping from one chamber to another. 4. Manholes: chambers with working space at drain/sewer level used for entry of personnel and equipment. Robust and relevant advice As design guidance develops over the years, it is easy to lose sight of the technical justi• cation behind the original advice. BSI Committee BSI B/505/22/P6 has carried out some excellent and thor- ough work in challenging the text of the National Annex and ensuring it is based on sound and clear principles. Examples include recommended spacing between access points (the table now follows logical reasoning), updated stand- ards (text and tables cover current market products, linked to consistent de• nitions), and good design principles to minimise problems in service (such as quick and easy access for inspection, cleaning and maintenance equipment which prevents equipment from getting stuck). The BPF Pipes Group is pleased to be able to o– er this new guidance and welcomes the update to EN 752: 2017 and its UK National Annex. These together will go a long way to providing end users of the guidance with clear information and will be of consider- able bene• t for projects going forward. Taking these improvements through to Sewers for Adoption 8th edition would directly bene• t developers and design- ers who currently rely on manufacturers' advice to interpret the over-complicated information given in the 6th and 7th edi- tions. The challenge for the water industry is to ensure that good quality and resilient infrastructure is constructed by both developers and self-lay providers. Clear, consistent and robust guidance that all parties can use will go a long way towards achieving this. well placed therefore to provide expert input to the BSI committee to update the National Annex to EN 752 which now clar- i• es and simpli• es best practice, explains and emphasises the importance of design and product choice on safe working, and ers, to adopt above-ground working as the new default, and having to justify where below-ground working is needed (for example in deep installations and at high maintenance points). This applies even for large diameter public sewers. To help, the new Annex has addressed the confusion over clear opening sizes for access points by explaining the reasoning behind sizing, and by providing consist- ent and easy to follow text which applies equally to private and public systems. Accurate and consistent defi nitions The BPF Pipes Group guidance shows how many di– erent terms are used to describe the same system components. Providing de• nitions which can be used across the industry will minimise con- fusion and save time. For example, the four de• ned access points are: