3.1 Estimations of oil slick thickness are useful for:

3.1.1 Estimating amount (volume) of oil in an area,

3.1.2 Positioning oil spill countermeasures in optimal locations,

3.1.3 Evaluating a spill situation,

3.1.4 Estimating volume for legal or prosecution purposes, such as for an illegal discharge, and

3.1.5 Developing spill control strategies.

3.2 This guide is only applicable to thin sheens (sheen and rainbow sheen up to about 3 μm). Thick oil and water-in-oil emulsions do not show visual differences with respect to thickness (1, 2).3

1.1 This guide provides information and criteria for estimating the thickness of oil on water using only visual clues.

1.2 This guide applies to oil-on-water and does not pertain to oil on land or other surfaces.

1.3 This guide is generally applicable for all types of crude oils and most petroleum products, under a variety of marine or fresh water conditions.

1.4 The thickness values obtained using this guide are at best estimates because the appearance of oil on water may be affected by a number of factors including oil type, sea state, visibility conditions, view angle, and weather.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.