Listen very carefully

Environmental noise, in common with other pollutants, is becoming an increasingly important factor with regard to the development and operation of industrial sites. This is particularly true for installations which seek to operate 24 hours a day, seven days a week.

Sound effect

One of the key aspects of the IPPC Directive, and other environmental management initiatives (e.g. ISO 14001 and EMAS) adopted by major industrial operators, is the principle of proactive management for defined environmental issues. The principle here is that

the effect of a modification or change within a site should be quantified and assessed prior to the action. Also, regarding the IPPC Directive, it is the ability to determine the effect of a modification which allows discussion and definition of a “substantial change”, and hence any need to review site permitting arrangements.

ATL has considered the implications of such an approach to the management of environmental noise and believe the following questions are relevant to sites which will be covered under the IPPC Directive. The same questions are also relevant if noise is considered a significant environmental factor within the terms of an ISO 14001 management system.

• Does the site have an existing planning condition relating to noise?
• Does the site comply with this condition, if so what evidence supports this?
• If the terms of the planning condition became part of an IPPC authorisation, how would compliance be demonstrated and how would the permit be reviewed?
• How would the effect of a change at site (addition or removal of plant) be quantified? And hence, how would desired noise limits for a change at site be defined and communicated?
• How does the site quantify noise emissions?

By answering the above questions, it is possible to begin to consider an asset’s requirements with respect to the management of environmental noise.

Demonstrating compliance

Typically, for major UK installations, sites do have planning consent conditions relating to noise, and compliance or otherwise is demonstrated through surveys under representative conditions. In general this approach is appropriate for demonstrating compliance, with additional work commissioned to address specific complaints or identified exceedances of limits. However, using such an approach can prove difficult when proactively managing noise emissions and auditing noise management actions.

To identify the significance of an individual noise source or groups of sources at an industrial site in relation to the resultant environmental noise levels requires an understanding of the acoustic source strengths and propagation characteristics between source and receiver. For many sites, this information is collated at design stage by development of noise models used to establish the environmental impact of the development. By continuation and update of such it is possible to establish validated “as built” noise models for operational sites.

This results in a tool which enables “cause and effect” interrogation and allows review of the consequences of potential changes on site environmental noise emissions. The uses and benefits of such an approach are primarily as follows:

• To assess the significance of new capital plant modifications on environmental noise levels at an existing site. This can be used to assist discussions with respect to the requirement to review a permit or define a planning limit. It enables the definition of noise limits for the new plant within an overall noise management programme, allows the positive effect of any equipment to become redundant to be established, and gives the operator a means of articulating required limits and proposals to contractors and regulators.
• To facilitate the periodic review of an environmental noise permit (which may be required as part

  of the IPPC process) and provide status information with respect

  to emissions. The approach allows operators to define what effect specific noise control actions

  will have on overall noise

  emissions, thus, if necessary, selecting the most cost-effective noise control options and

  discounting others.

• To allow environmental noise to be considered as part of ongoing maintenance and replacement activities at site. The approach can be used to link environmental noise to planned maintenance activities and ensure that over a period of time environmental noise levels are reduced where practicable. The approach allows this to be achieved in a deliberate and managed way and would support the principles of an environmental management system.

Sound practice

Using the above approach, ATL has implemented Environmental Noise Management (ENM) Systems at two major operational oil and gas sites in the UK that facilitate the proactive management of environmental noise.

These systems are designed to “live” with the plants and form the basis of ongoing noise management and planning actions. The approach is equally applicable to new Capital Plants.