Adding weight: rating significance

11th November 2012


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Anya Ledwith on the best ways to rate the significance of environmental aspects within an environment management system

The foundation of a good quality environment management system (EMS) is an understanding of the organisation’s aspects and impacts. This information should be used to recognise the need for, and determine the type of, operational controls required. Developing a process to rank these aspects for significance ensures that the EMS is not overwhelmed from the start.

Avoiding confusion

There is sometimes confusion in differentiating between environmental aspects and impacts. ISO 14001 defines aspects as activities, products or services that can interact with the environment, while impacts are any change to the environment (adverse or beneficial) resulting from an aspect.

So, for example, consider business journeys by car:

  • activity – driving a car
  • aspect – use of diesel as fuel
  • impact – resulting air pollution

In its initial environmental review, the organisation will look for aspects and impacts relating to all activities, products and services. This is a detailed process covering normal, abnormal and emergency conditions, to identify aspects arising from its past, existing or planned activities. It should consider the aspects that it can control (such as its own energy consumption) or those it can influence (the activities of its contractors). Organisations are not expected to manage issues outside their sphere of influence or control.

The scope of the environmental review extends across the organisation, from the back office to manufacturing lines, service delivery and business travel. It should examine the materials used and wastes produced, as well as the activities of contractors, suppliers and even customers. Producing an “aspects register” that also details arising environmental impacts is an extensive process and one that often results in copious amounts of information which will need to be managed.

Taking precedence

Normal conditions, by their definition, are more common than abnormal or emergency situations, but which take precedence? Similar sites may have different operating times, or levels of output, but can they be addressed in the same way? Is it possible to compare a few kilos of hazardous waste to large quantities of paper? Meanwhile, some aspects will have greater impacts or are regulated by legislation, so should they receive the same attention as others?

Clearly, an organisation cannot and should not manage everything equally and all at once; it needs to prioritise so the more important (or significant) aspects are dealt with first and/or with greater scrutiny.

Significance ratings allow an organisation to decide on the appropriate control measures and timescales, enabling it to manage its environmental aspects in a considered manner.

So, what is significant? If we look to 14001; it states that a “significant environmental aspect has, or can have, a significant environmental impact”.

However, 14001 does not specify requirements on how to determine significance. The EMS general guidelines (ISO 14004) are a little more helpful, noting that significance can be applied either to environmental aspects or to their associated impacts, usually the latter. Often, a mixture of the two is evaluated while considering:

  • environmental criteria (such as impact severity or frequency of the aspect);
  • applicable legal requirements (like specified waste quantities or discharge permit limits); and
  • stakeholder concerns (for example staff interests, public image, noise or odour).

Evaluating significance involves both technical analysis and judgment, so one person may interpret the results differently from another, and what applies to one organisation may not apply to another.

Providing consistency

Establishing formal criteria should help to provide consistency. ISO standards, of course, require records to be kept. A documented procedure is essential, but it should not be overly complex (leaving it difficult to understand) or too simplistic (forcing many assumptions to be made), otherwise there is a risk that variations will be introduced.

The methodology must be relevant to the organisation using it: an office-based company and a manufacturing firm, for example, will have distinct aspects that affect the environment and the businesses very differently.

There are numerous and varied methodologies, developed by organisations from different sectors over the years. Examples include:

  • Cardiff & Vale NHS Trust uses a simple 5x5 scoring matrix, which scores aspects and impacts against two broad categories: “control” and “severity”. Control of the aspect is scored from one, where there is a high degree of control in place, to five, where there is negligible or no control. Severity of the impact ranges from one (insignificant or positive impact) to five (severe). The scores are multiplied to give results up to 25 and ranked as low significance (1–6), medium (8–10) or high (12–25).
  • Electronics manufacturer Raytheon Systems also uses a 5x5 matrix, which compares “likelihood” against “severity”, with a maximum score of 25. Although legislation is not included in the numerical scoring system, it is considered in the aspects register, which, at nearly 300 lines long, includes a range of aspects, such as energy consumption, use of chemicals and disposal of hazardous waste. Unusually, each aspect is scored twice, both before and after controls are implemented, to show how risks are managed.
  • Design and print company Easibind, by contrast, uses a two-stage approach, which compares “likelihood” and “severity” and includes a detailed procedure for evaluation. A risk matrix is used to provide risk ratings (from very low to very high) rather than a numerical score. These ratings are used to classify the aspect (see below).
  • Crawley Borough Council uses a comprehensive method to consider a range of issues, including influence, severity, duration, cumulative effect, legislation and stakeholder interest. A single score (from one to five) is given, with four or five deemed significant. This process, while thorough, appears more complicated to follow than a matrix without detailed guidance on scoring.
  • Accountancy firm KPMG has an interesting approach, which recognises the nature of the organisation and its associated aspects. Each aspect or impact is assessed against a set of clearly defined criteria at the function level, producing scores of one, two or three. The sum of the scores for each aspect is then ranked as having a high environmental significance (if it is more than 11), limited significance or no significance. The criteria used to assess the severity of environmental impacts include: business disruption, financial loss and reputation.

Perhaps one simplified matrix is too basic for the range of aspects likely to be encountered. A slightly more detailed system, tailored to the relevant needs and activities of the organisation, is preferable.

A bespoke risk matrix could, for example, include categories such as CO2 emissions (amount of carbon produced); frequency (how often the aspect occurs); severity (degree of impact on the environment); likelihood (probability impact will occur); controllable (extent of control or influence, and resources required); and regulated (degree of regulation).

These are fairly standard categories, but a tailored approach means they can be supplemented by others that are important to the organisation, such as stakeholder interest, financial impact or business continuity.

Each category must then be scored for significance – using five levels of severity is a common approach. Taking the above categories as examples, these levels could range from “minimal” to “major” for CO2 emissions; “seldom” to “repeated” for frequency; and “improbable” to “very likely” for likelihood. Short explanations should support the terminology, clarifying, for example, that “intermittent” frequency means occurring at intervals of one to six months, while “regular” means intervals of one to four weeks.

Scoring is then applied on a scale of 1–5, with, for instance, “minimal” carbon emissions scoring one, and “major” scoring five. Under such a matrix, an overall score of 19 or more would be regarded significant.

Ongoing process

Whichever method is chosen, determining significance is not a one-off project. It should be undertaken regularly, and particularly when there has been changes to activities; after the acquisition of new sites; or following an incident. 14001 auditors look for a formal procedure that is properly understood and applied. Non-conformances may be raised against the method, but are more likely to arise from how it is applied.

When developing an approach, keep it simple, make it relevant and ensure it is replicable. And don’t forget to review it regularly.


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