Transcript Plant Protection

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.
Plant Protection Process
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
Plant Protection Process
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.
Plant Protection Process - Plans
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.
Plant Protection Process - Plans
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.
Plant Protection Process - Plans
Some common abbreviations on our plans:
Pressures:
HP – High Pressure
IP – Intermediate Pressure
MP – Medium Pressure
LP – Low Pressure
Examples:
315 PE M/P (metric)
4” DI (imperial)
Pipe Materials:
ST – steel
SI – spun iron
CI – cast iron
DI – ductile iron
PE – polyethylene
AS – asbestos (few!)
CH/SH – cast/spun hoselined
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
Death or major injury to:
- You and/or your colleagues.
- Others affected by your work (e.g. public, other trades).
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.
Consequences of damaging a gas pipe
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.
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).
How can you prevent damage to gas plant?
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!
How can you prevent damage to gas plant?
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 Close
Celtic Springs
Coedkernew
Newport
Wales NP10 8FZ
General tel. no.:
02920 165 0597
Plant Protection Team:
02920 278912
National Gas Emergency Hotline: 0800 111999