Welcome to the Winter 2014 edition of Pipelines, your eNewsletter from CPSA.
In the Spring 2013 edition of Pipelines we discussed the introduction of a new National Standard for sustainable drainage (SuDS). It was expected to come into force in April 2014. Well, that didn’t happen – and we are still waiting! In the intervening period, the bank of knowledge and reference material has grown, through excellent sources such as Susdrain. Some important changes have taken place, not least the launch of a new consultation on SuDS by DEFRA and DCLG. See below for more information on the proposed changes and what it may mean for SuDS.
Also in this issue, a reminder of the considerations for air testing newly constructed sewer pipelines, including a video providing helpful, practical guidance.
We have also included a link to the full CPSA video library. There’s a wealth of useful and interesting information in there.
If you are up to speed with social media, CPSA is well served on numerous platforms and we also have a blog, so why not get connected?
And don’t forget, we have a number of free CPD seminars to keep your professional development up to date, independently accredited by CIWEM and Construction CPD Certification Service. These are available to book at your office or other suitable location.
Stuart Crisp, Director, Concrete Pipeline Systems Association
We’re delighted to announce we are a Susdrain Supporter
CPSA has joined an impressive cross-sector group of organisations dedicated to supporting the www.susdrain.org initiative, further demonstrating growing industry support for widespread delivery of Sustainable Drainage Systems (SuDS).
Over the next two years, it is anticipated that there will be a significant increase and improvement in the delivery of SuDS, with positive change driven by new guidance and the potential implementation of National Standards for Sustainable Drainage.
Susdrain will help support improvements in SuDS delivery through a range of initiatives including new resources, summaries of the latest guidance, case studies and a series of topical SuDS events.
CPSA is one of 29 organisations including Defra, the Environment Agency and other key industry players involved in the project from September 2014.
Since its launch in 2012, Susdrain has provided a valuable range of resources for those involved in delivering SuDS. Susdrain will continue to support drainage and highways engineers, planners, urban designers, landscape architects, land or housing developers, suppliers, flood risk managers, biodiversity / environment managers and the general public to increase knowledge and confidence in the delivery of SuDS.
New SuDS consultation – for better or worse?
On 12 September 2014, Defra and DCLG launched a joint consultation document, which set out a possible approach for implementing sustainable drainage systems and mechanisms for ensuring their long term maintenance. There are some important differences between the proposed new approach and the previous direction that the industry was heading.
The proposed new approach may avoid delays to the planning process, compared with the SuDS Approval Body (SAB) approach, but SuDS and drainage expertise is still required. This is not generally found in the town/district/borough councils and therefore may have to be sub-contracted. The anticipated general consensus to the consultation is that the proposed approach is the path of least resistance and therefore could see SuDS delivered more quickly. There is however concern for the quality that will be delivered.
Fires in sewers, combustible pipes and pipeline integrity – is it worth the risk?
On 28th September 2014 fire-fighters were called to a fire at a building site at Cargo Fleet Lane, Middlesbrough after reports that 20 large plastic sewerage pipes had deliberately been set alight. The blaze resulted in the streets surrounding the site having to be cordoned off after the area was blanketed in a cloud of noxious black smoke.
Similar incidents have been reported in America. One such example is where children playing in a 42″ diameter storm culvert built a fire to keep warm; this then set light to the HDPE pipe which resulted in fire damage spreading for over 800′ along its length.
It is not just arson that pipe users need to be aware of, brush fires, vandalism, fuel spills and industrial accidents all have the potential to initiate fires in pipelines. As a result, designers, installers and asset owners should consider combustibility and the risk of fire when selecting pipe materials, gully tops and drain gratings.
Plastic burns. If these pipelines had been constructed from a non-combustible material, such as precast concrete, it is unlikely that either of these fires would have occurred, simply because concrete does not burn.
Where a fire has occurred in a drainage pipeline a secondary consequence of a fire is the impact of the fire on the pipe itself. Fires in concrete pipes generally do not affect their structural strength, flow capacity or corrosion and abrasion resistance, whereas plastic pipes can melt and collapse.
All of which raises the question: is the use of drainage pipe materials other than concrete really worth the risk? Concrete has inherent strength and a proven service life of over 100 years … and it is non-combustible.
Leak-Tightness testing in pipelines
All newly-laid drainage pipes, including manholes, should be tested for leak-tightness prior to backfilling.
There are two basic tests; the air test and the water test. An air test involves using inflated stoppers at both ends of a section of the pipeline under test. Pressure is then introduced into the section of pipeline and after a stabilisation period the pressure is checked. In the event of a single or continued air test failure, recourse to a water test is allowed and the result of the water test alone shall be decisive.
A water test involves creating a head of water in the pipeline which is examined for tell-tales signs of leakage. Following a period of settlement and acclimatisation, the level of water in the header tank is monitored for a specified period and the loss of water measured and checked. It is not unknown for a pipeline that has failed an air test to pass a water test.
For more information about leak-tightness testing refer to BS EN 1610:1998 – Construction and testing of drains and sewers.
We have a video on how to air test concrete pipelines on our YouTube channel. Please click here to view the video