robinson house, westlakes science park, moor row, cumbria

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of 22 Letterhead issue 1 July 2008 Getting the Best out of Engineering Think before you print Think before you print –– save save

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Robinson House, Westlakes Science Park, Moor Row, Cumbria CA24 3HY, UK Email:[email protected] Web:www.vhe.co.uk/shepley Tel :[0044](0)1946599022 Fax :[0044](0)1946591933

Introduction Shepley Engineers Limited (SEL) is a wholly owned subsidiary of Renew Holdings plc. A major multi-disciplined contractor and project management group specialising in term contract works predominantly within the nuclear and chemical process plant environments. SEL is one of the leading companies on the Sellafield nuclear site that specialises in Tungsten Inert Gas (TIG) welding which is a principle that fuses two similar or dissimilar metals together such as in stainless/carbon steel process pipe lines, stainless/carbon plates, exotic materials and general fabrication projects. The process of TIG welding requires a shield gas to be dissipated over the local area to prevent impurities such as metal defects and air entering the molten metal pool, which could result in a defect weld requiring either the weld being partially repaired or entirely cut out and re-welded, A secure weld is required due to the probability of both conventional mediums such as acidic and radiological liquids flowing through the welded pipe systems. Welders are also often exposed to dangerous gases and particulate matter. Processes like flux-cored arc welding and shielded metal arc welding produce smoke containing particles of various types of oxides. The size of the particles in question tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, many processes produce various gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate. The 3 main toxic off gasses caused by TIG welding are 1 – Nickle Nickle metal can affect the body if it is inhaled or swallowed. It may be absorbed through the skin causing systemic toxicity. Nickle particles have the potential too be respiratory irritants and skin contact may cause an allergic skin rash. Exposure to soluble nickel may cause giddiness and nausea. 2 - Chromium V1 Chromium V1 compounds are considered very irritant and corrosive. Chromium V1 can give rise to skin irritation; can cause burns, dermatitis and some sensitisation. If the substance enters through cuts in the skin, chromic ulcers may result and can penetrate to the bone underneath. Inhalation of chromium V1 produces an irritation of the mucous membranes and causes shortness of breath and wheezing. It is classed as carcinogenic. 3 -Ozone Short term exposure to ozone may cause an individual to notice sharp, irritating odour. As the concentration increases, the ability to smell and recognise ozone may decrease. Irritation of the eyes, dryness of the nose and throat and a cough may also be experienced. Due to the hazards explained above whilst TIG welding and with the difficulty of producing a complete shield gas requirement (purge) for producing class A1 welds and whilst every possible

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control method can be utilised to eliminate or reduce the off-gas hazards, it is still necessary to utilise engineering methods such as using local exhaust ventilation (LEV), these in turn had the adverse effects of blowing the purge gas away and he resultant was unacceptable weld integrity. In 2002 SEL using expert advice including major welding equipment producers and welding specialist companies such as: -

Metrode products Ltd. ESAB Group (UK) Ltd. BOC Gases Air Products Ltd. SEL subject matter expert AJ Wareing (MSC in metal & welding techniques) SEL Mechanical & Welding specialist H O`Reilly (Welding inst.) SEL Quality assurance manager R Donohoe.

The resultant combined information was collated and calculations based on the factual data supplied by the manufactures and other suitable qualified experience personnel (SQEP) and evidence have been attached: - Assessment of the production of Welding Fume during Tungsten Inert gas (TIG) in an Enclosed area. Evidence 001 Review of assessment based on 2002 calculation has constantly been monitored by SEL key personnel to ensure the TIG welders exposure is minimised. SEL ensured that the relevant information gained from the calculations was imputed onto their Management System (SWIM`s) arrangements, where all sites and specific project procedures can be implemented and complied with when similar tasks are being taken. With new technology and different working techniques SEL senior management decided that they would engage an occupational hygiene company to carryout a comprehensive survey including air sampling and personnel sampling of the welder while carrying out TIG welding. To ensure SEL covered all aspects of the TIG welding process for the survey it was agreed that three different welders working in completely different environments would be monitored wearing personnel air samplers.

The first welder carried out two 75mm stainless steel welds one with and one without LEV In a work shop environment. The second welder carried out one 75mm stainless steel weld in a similar environment

where the calculation testing took place in 2002. The third welder was monitored welding on a construction site.

Evidence 002 Since the first calculation testing was undertaken Shepley Eng. Ltd have acquired a company called West Cumberland Eng. Ltd. (WCEL) which is a series of large work shops and WCEL manufacture large stainless steel structures and carryout TIG welding on various sizes of pipe, structural box sections and stainless steel angle bars. SEL introduced the findings of the calculation survey and are also using the information of the air sampling survey to ensure WCEL TIG welders exposure is minimised. To ensure the information was cascaded to the personnel involved (all SEL welders), H O`Reilly (Site Director) delivered effective communication and interactive discussions occurred which ensured the information was understood.

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At WCEL a different type of welding is carried out called Metal inert gas (MIG), which also requires shield gas, however the shield gas is not as critical as with the TIG process and LEV can be used more effectively. Although with MIG welding the shield gas is not as critical as TIG welding and local exhaust ventilation is a more successful engineered control Shepley Group senior management are continuing being pro active and ensure that their employees health and welfare are paramount they have organised for the occupational hygiene company to carryout out air and personnel sampling on WCEL MIG welders and will again act on the findings of the survey report. Summary Although both surveys involving TIG welding process which were carried out on behalf of Shepley Group have shown that the welders were exposed to low concentrations of chromium V1 and Ozone, which was below all relevant Workplace Exposure Limits (WEL), however Shepley Group will always ensure that all their employees health and welfare will always be their priority and will continue to strife to improve working conditions. Shepley Group always ensure that if new technology or additional information becomes available they will explore all avenues and where possible introduce them at the earliest opportunity. Appendix Evidence 001 Assessment of the production of Welding Fume during Tungsten Inert gas (TIG) in an Enclosed area. Evidence 002 Occupational hygiene company report Evidence 003 Photographs of TIG welding sampling Evidence 003 Shepley Group Operating Experience Feedback (OEF)

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robinson house, westlakes science park, moor row, cumbria

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