Plant Protection - Gas Jeff Smale, Plant Protection, Wales & West Utilities Ltd. 08.05.09.

Plant Protection - Gas

Jeff Smale, Plant Protection, Wales & West Utilities Ltd.

08.05.09

Objective

• The gas network – an overview

• Our plans and paperwork

• Consequences of damage

• Damage prevention – what you can do

The Gas Network

Who are Wales & West Utilities Ltd.? (WWU)

We transport gas throughout Wales and the South West.

Approximately 34000km of gas distribution pipelines.

Covers approximately 1/6th of the UK, 7.4 million people.

Operates gas emergency service. Extends gas distribution network. Replaces gas distribution pipes and gas

meters. Does not sell gas.

Image © National Grid Gas

The Gas Network – An Overview

National Transmission System – High Pressure:→ Distributes gas around the country.→ Steel pipelines operating up to 85bar (1250 PSI). (ave. car tyre pressure is around 30 PSI!)

Intermediate Pressure→ Distributes gas throughout regions to populated areas.→ Steel and some high density polyethylene operating at 7bar (100 PSI).Medium Pressure (see pipe and marker tape)→ Distributes gas to/around towns/cities, direct to high volume consumers.→ Metallic and polyethylene mains operating up to 2bar (29 PSI).

The Gas Network – An Overview

Low Pressure: (see pipe and marker tape)→ Delivers gas to majority of consumers via mains in roads.→ Operating pressure varies, up to a maximum of 75mbar.→ 30 year replacement programme – replace metallic mains with

polyethylene.→ Various materials – polyethylene, ductile/spun/cast iron, some

historical materials such as asbestos.Service Pipes:→ Typically small diameter pipes that supply gas to individual properties.→ Service ends at the emergency control valve and meter.

Plant Protection Process

The most important thing you can do is…

CONTACT US!

Give us as much notice as possible – at least 28 days. Contact our head office, in writing, enclosing a plan showing the full

extent of your works. We will identify what plant is affected and respond to your enquiry. If our plant is affected we will return a plan and supporting

documents. We then contact our local manager to make contact with you and

arrange a site visit if necessary.

Our process is based on risk, for example:

The pressure regime of the plant affected The nature of your works The complexity of our plant in the area Any other special engineering considerations


During the site visit we will give advice and guidance as to how to prevent damaging our plant.

If our plant or your safety is at risk, we will ask you to stop work.


It is essential that you have plans available to you before commencing work.These must be less than 28 days old.If on CD, make sure the disk is current.Plans must not be transposed on to one master site plan.Those doing the work must be aware of the presence of gas apparatus and the controls in place.Read and understand the information at the bottom of the plan.

Plant Protection Process - Plans

Our highest instance of damage is medium pressure plant.

In most cases, those causing the damage were aware of the presence of gas plant.What can you expect from us if you contact us and MP is affected? A plan with a warning label. General Conditions for Protection.


Additional General conditions for you to complete prior to work. Site visit(s) if appropriate.

Gas pipes are shown as follows:

High Pressure(broken orange line – 3 dashes)

Intermediate Pressure:(broken green line – 2 dashes)

Medium Pressure:(broken blue line – 1 dash)

Low Pressure:(solid red line)

Note: WWU plans show only WWU mains. Services are generally not shown.


Some common abbreviations on our plans:

Pressures:HP – High PressureIP – Intermediate PressureMP – Medium PressureLP – Low Pressure

Pipe Materials:ST – steelSI – spun ironCI – cast ironDI – ductile ironPE – polyethyleneAS – asbestos (few!)CH/SH – cast/spun hoselined

Examples:315 PE M/P (metric)4” DI (imperial)


Ilchester, medium pressure gas main, 2000 – burns, hospitalisation, evacuations…

Belgium 2004

15 fatalities 120 injured

“There were bodies in parking lots, in the fields; burnt out cars in an area half a kilometre wide"

Consequences of damaging a gas pipe

Loss of gas supply – potentially significant and costly to rectify.Loss of other utilities.Damage to property.Interruption to your works.Investigations – Police and/or HSE (if death/major injury), Wales & West Utilities.Enforcement Action.Prosecution – company and/or worker.Unlimited costs and liabilities.

Death or major injury to: - You and/or your colleagues. - Others affected by your work (e.g. public, other trades).

Following interference damage, Wales & West Utilities will: Notify the HSE under RIDDOR Notify the HSE under GS(M)R Conduct an investigation – immediate and root causes

HSE may decide to undertake their own investigation.

Consequences of damaging a gas pipe

The Facts and Figures – 2007/08

For 2007-08, 52% of all reportable* gas-related incidents were from third party damage.

The Causes? Human error – e.g. mistakes, not following rules, taking shortcuts. Poor or inadequate planning. Breakdowns in communication.

Each incident was an opportunity to suffer death and major injury….

* Reportable under GS(M)R – fire/explosion has occurred or was likely to occur.

How can you prevent damage to gas plant?

Contact us before you start work! Ensure current plans – preferably colour – are easily available to

those doing the work, used, and understood. Ensure accompanying paperwork has been read and understood

by those doing the work. Complete Additional General Conditions before starting work. Ensure the presence of gas pipes have been confirmed by hand

dug trial holes prior to using a mechanical excavator. Use clues on site to alert you to the presence of gas plant (see

furniture label).

Follow guidance given by Wales & West Utilities:

Low pressure – paperwork returned to you is usually sufficient. Medium pressure – paperwork and site visit – 3m exclusion zone

either side of the position of the main will be marked out by WWU, don’t use mechanical excavator within it until line/level of main(s) are identified by you.

Intermediate/high pressure – all work supervised by WWU. Document “SSW22” issued with all HP work.

If in doubt – stop work and ask!


Designers/Planners and Organisation Aware of: HSG65 “Successful Health & Safety

Management” HSG47 “Avoiding Danger from Underground

Services” CDM 2007 – avoid foreseeable risks SFAIRP

Operatives/Supervisors Aware of guidance in HSG47 Appropriate experience and qualifications Aware of specific site conditions


Report all instances of damage:

Minor damage can cause pipeline failure in the future – including damage to pipe coatings. Report to your WWU contact or the National Gas Emergency Hotline (24/7). Be aware that we have other plant connected to gas mains, such as cabling for cathodic protection (helps prevent corrosion on steel mains).

All damage resulting in a release of gas MUST be immediately reported to the National Gas Emergency Hotline: 0800 111999.Evacuate the area, prevent approach by public/workforce, extinguish/prevent naked flames within 15m. DO NOT ATTEMPT TO REPAIR, RESTRICT THE FLOW OF GAS OR OPERATE ANY LINE VALVES.

Useful Contacts:

Wales & West Utilities:Wales & West House Spooner CloseCeltic SpringsCoedkernewNewportWales NP10 8FZ

General tel. no.:02920 165 0597

Plant Protection Team:02920 278912

National Gas Emergency Hotline: 0800 111999