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Water, Water – Everywhere

Published: 4th Sep 2013


If genuine learning from bitter experience accompanied confined space catastrophes, the importance of safety training wouldn’t be as great as it is. But as Jeff Murphy explains, it’s of vital significance to many industries.

A case study

A worker entered a storage tank to remove sludge from the bottom of it. The tank had not been tested, evaluated or ventilated prior to entry, and the operator wore no personal protective equipment (PPE).

It was realised that the operator had became unresponsive to communications soon after entering the tank. The operator’s co-worker, who remained outside the tank, called verbally for help from his supervisor and foreman.

Management at the plant reacted quickly and decided on rapid retrieval of the operator. They ‘put together’ an untrained rescue team and found that the only access into the tank was through a 400mm diameter manhole on top of the tank – an opening too small for any of those trying to rescue physically to pass through.

The ‘rescuers’ therefore decided to cut a larger opening into the side of the tank using a rotary saw. While the cutting operation was underway, sparks from the saw blade ignited vapours within the tank. The resulting explosion killed one of the rescuers and injured 14 others at the site.

The judgement of the autopsy subsequently performed on the worker who first entered the storage tank and collapsed, decided that he was already dead at the time of the explosion.

The company directors and managers responsible for the site were deemed to be negligent in their responsibilities to their workforce and consequently paid a substantial fine which almost bankrupted the company.


The rising number of fatalities and injuries that occurred throughout industry while people were working in the many and varied confined spaces led to the drafting and enactment of specific legislation to address this area of industrial activity. This resulted in the introduction of The Confined Spaces Regulations 1997. These became lawful for the UK workplace from 1998.

Working with water in a confined space

Working within the usual confined space scenarios brings many and varied risks directly to workers and indirectly to managers and supervisors. What are perhaps less well known are those aspects of risk associated with working in a confined space when it is combined with a water environment.

Here we are talking about any confined space task which includes the possibility that water or other gases/fluids might impinge upon the performance and wellbeing of personnel actively working within a space which comes within the criteria as defined by Water UK Occasional Guidance Note (OGN) 2.2, dated October 2009.

The problem

Following on from the original introduction of Confined Space Regulations in 1997 the UK water industry experienced a period when it became apparent that each water authority had its own interpretation of the regulations, particularly as they were being applied to outside contractors seeking to provide particular services. The major contributing factor to the development of this situation was that the existing regulations, having been drafted without a ‘water’ aspect, were open to differing emphases by assigning authorities.

Water companies had, for many years, entirely recognised that special hazards and risks were associated with water specific confined space working. Historically, a range of focused and well structured Policies, Procedures and Arrangements (PPAs) had evolved within individual water companies. These were designed to ensure that firstly confined spaces work was carried out safely in accordance with the approved UK regulations, and secondly with guidance so that all proper controls were also in place.

Although all UK water organisations and contractors have well documented health and safety procedures, there was room for some confusion. The structure of the water industry continued to evolve in line with both market forces and as driven by the general thrust of existing legislation.

Considerable improvements in both customer service and the level of environmental protection do mean that past local working methods have the potential to be less well understood. In particular, the increasingly widespread employment of outside contract labour introduced a wide variety of methodologies and practises covering everything from training, entry and rescue to medical requirements.

The solution

As a result, the UK Health and Safety Executive (HSE) consulted with the various water authorities and requested that industry guidelines, designed particularly for its own environment, be agreed and published. The Water UK Occupational Health and Safety Group (WUKOHSG) was co-opted to supervise production of suchall-encompassing procedures, which would bring some clarity and uniformity to risk assessments and ‘downstream’ controls and training parameters, without completely removing the existing methods of working which had been successful for individual organisations. In addition, a further WUKOHSG’s objective had been to facilitate the wider movement of outside contractors between client water companies and authorities, with reduced scope for confusion of applicable standards and hence lower retraining costs. There were other related objectives also – not least being the rationalisation and standardisation of medical ‘fitness for entry’ requirements covering entry into water confined spaces.

In the years following the introduction of UK wide regulations the majority of work in these confined spaces was undertaken on behalf of the water companies by a variety of approved Direct Labour Organisations (DLO). Recently, however, increased use has been made of indirect labour and this has resulted in several adaptations of the PPAs by some individual water companies to include specific instructions to contractors.

The result was a wide range of specifications leading to a lack of consistency in the skills, training standards and safety equipment being demanded of contractors before they were permitted to undertake work in each water company’s confined spaces.

It is important to recognise that this diversity in PPAs was not, in itself, an overriding issue for any particular water company or its nominated DLO. Nor was it, in that timeframe, a major issue for any contractor, many of whom were small local firms often working only with one regular client water company.

The contracting world in today’s workplace is very different, however, with a growing portfolio of organisations capable of providing requisite labour skills across water company boundaries with some scaled up and able to provide some form of national coverage. Thus arose the quite urgent requirement to reduce significantly the risk of confusion among nation-wide/multi-client contractors – a confusion which had the potential inadvertently to foster potentially unsafe working environments.

As an interim solution and to help compensate for the existing diversity of PPAs, several water companies required bidding contractors to purchase bespoke training outcomes to meet their own specific safety procedures. Although recognising the unsatisfactory state of affairs this ad hoc solution merely added to the potential for misunderstandings and a more controlled and centralised recognised standard was needed.

The resultant variety of company specific PPAs also meant that each contractor’s staff was being trained, and often retrained, several times over, to meet each particular water company’s requirements. In addition to the obvious burden upon training budgets, it is was felt that the cumulative overexposure of contractors and staff to such variations of confined spaces training would lead to a possible devaluation of the importance of the original purpose of the previously agreed regulations.

Consequently, at a subsequent Water UK Health and Safety Horizontal Group meeting in 1998, it was agreed that a solution to minimise this worrisome diversification of confined space entry requirements being randomly applied to contractors should be sought, and the WUKCSMG was tasked with devising an agreed rationalisation of confined space entry requirements for use by contractors.

Working closely with the HSE, the WUKCSMG has agreed a methodology focused on four standardised National Classifications – NC1 to NC4 – for confined space entries within the water industry. These have been carefully drafted to ensure that a contracting manager could overlay a local water company’s classifications and express the requirements to contractors in nationally recognisable terms and training standards.

This solution not only avoided compulsory changes to extant PPOs for DLO but also provided a unique national standard for use when individual water companies were specifying to potential contractors. All concerned with this rationalisation process were careful to keep in mind the overriding need to maintain the highest level of safety and protection for the staff of all contractors.

National Classification (NC) system

The National Classification (NC) system recognises that the system of work or precautions that may have to be taken for entry into a confined space will differ with the hazards – real or assessed – the degree of risk, complexity of the operation and its physical/geographical location.

The National Classification system established by Water UK for confined space entries made by contractors to water company properties identified four entry categories designated NC1, NC2, NC3 and NC4. Water companies, however, may have their own classifications. Nevertheless, they will be able to relate these to the new classifications, as low, medium or high risk confined spaces, from within the existing National Occupational Standards (NOS).

All potential working environments defined as confined spaces within the extant regulations requirea risk assessment, which (inter alia) considers:

  • The need for entry to complete the task in hand cannot be avoided
  • The intrinsic hazards likely to be present in the particular workplace
  • Particular conditions and circumstances likely to increase or decrease risk
  • Any additional hazards likely to be introduced by the task in hand, such as fumes, sparks or electric shocks
  • The extent to which risk can be eliminated or controlled through either engineering controls or the system of work and competency of the operatives involved

This risk assessment will lead the assessor to a decision on the classification of the entry aligned with the Water UK National Classification Scheme for confined space entries. It is extremely important to note that it is the risk tied to the task-based entry which is classified and not the confined space itself, which will already be nominated as low, medium or high.

Classifications of entries

National Classification 1 (NC1)
NC1 – Low risk shallow entry with adequate natural or mechanical ventilation, where access is simple and unobstructed and there is no likely risk of flooding, e.g. meter pits, valve chambers, booster-pumping stations, PRV (Pressure Releasing Valve) chambers, all of which are usually associated with Low Risk Confined Spaces.

National Classification 2 (NC2)NC2 – Vertical, direct unobstructed access with continuous attachment to a man riding hoist or similar mechanical rescue device. Usually associated with Medium Risk Confined Spaces.

National Classification 3 (NC3)
NC3 – When it is not possible to have persons permanently attached to a safety line. Usually it will be a team entry which moves away from the entry point, e.g. man entry sewers, utility service subway tunnels, aqueducts and complex wet wells. Working without an attached rescue line and includes working away from the point of entry. Usually associated with Medium Risk Confined Spaces.

National Classifications NC1 to NC3 are intended as generic standard methods for safe working which will be selected in accordance with the usual risk assessment, and the known physical characteristics of the workplace.

National Classification 4 (NC4)
In a small number of cases the three standard generic classifications above, and their supporting control principles, will not totally address the assessed risks and thus the application of National Classification 4 (NC4) will then be appropriate. NC4 classified entries necessitate the development of a detailed written risk assessment and a task specific Safe System of Work (SSW). Where necessary the SSW will incorporate valving schedules, permits to work and gas test certificates.

Circumstances, which might lead to NC4 National Classification – and this list is not exhaustive – might include where:

  • Fluid, mechanical or electrical isolation arrangements are complex
  • Structural conditions are in doubt
  • Underground systems are particularly deep or complex
  • Record drawings are in doubt
  • There is a history of serious atmosphere hazard
  • Industrial waste discharges are insufficiently diluted to control harm from chemical, biological or radioactive agents
  • The risk of drowning is only controlled by pumping or by tide
  • The job involves hot work or a fume producing process
  • The job requires electrical apparatus operating above Safety Extra Low Voltage (SELV) 25 volts or which is not explosion protected
  • The work in hand is unfamiliar, complex or inherently hazardous
  • NC4 Non standard entries involving complex operations which introduce additional risks and require specific controls and rescue arrangements, e.g. mechanical hazards, physical complexity of system introduced hazards, enhanced specific intrinsic hazards

Application of National Classifications

For fuller details concerning the implementation of the National Classifications the following Sections from the Water UK Occasional Guidance Note (OGN) 2.2, dated October 2009, should be consulted and applied as necessary:

  • Section 4 - Principles of Procedures to be adopted by Contractors Working at ‘Water’ Confined Spaces
  • Section 5 - Self and Assisted Rescue at Confined Spaces
  • Section 6 - First Aid and Resuscitation
  • Section 7 – Medical Standards for Breathing Apparatus Wearers
  • Section 8 – National Occupational Standards (NOS) and Qualifications for working in confined spaces

Training outcomes

The regulated UK National Operating Standards are expressed as statements of competence and potential workers are assessed against these by approved training suppliers. Awarding bodies, such as City and Guilds, approve and operate a quality assurance system for centres wishing to carry out approved training courses.

This also results in a free and open market for training providers to foster competition and influence costs. Individual training providers can therefore innovate and best apply their professional skills in training course design and delivery, while ensuring that all successful delegates reach the prescribed output standard of competence.

Published: 04th Sep 2013 in Health and Safety International

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