BS EN 13725:2022

What is BS EN 13725 – Odour concentration about?

BS EN 13725 is a European standard that discusses the determination of odour concentration by dynamic olfactometry and odour emission rate. Stationary sources of air pollution, including factories, refineries, boilers, and power plants, emit a variety of air pollutants.

BS EN 13725 specifies an objective method for the determination of the odour concentration of a gaseous sample using dynamic olfactometry with human assessors.

BS EN 13725 also specifies a method for the determination of the odour emission rate from stationary sources, in particular:

• Point sources (conveyed or ducted emissions)
• Active area sources (e.g., biofilters).

Note: The field of application of BS EN 13725 does not include:

• The measurement of odours potentially released by particles of odorous solids or droplets of odorous fluids suspended in emissions
• The measuring strategy to be applied in case of variable emission rates
• Subjective methods for the sensory measurement of the relationship between odour stimulus and assessor response above detection threshold (perceived intensity)
• Direct measurement of odour exposure in ambient air. For this measurement purpose, field panel methods exist which are the subject of EN 16841‑1
• Direct olfactometry, including field olfactometry
• Static olfactometry
• Measurement of the odour identification (recognition) threshold
• The determination of odour emission rate from volume sources, such as fugitive emissions from buildings
• The determination of odour emission rate from passive area sources.

Who is BS EN 13725 – Odour concentration for?

BS EN 13725 on stationary source emissions applies to:

• Manufacturer of stationary emission measurement
• Quality control personnel
• Testing authorities
• Regulatory authorities

Why should you use BS EN 13725 – Odour concentration?

A dynamic olfactometer is an apparatus that delivers a flow of mixtures of odorous and neutral gas with known dilution factors in a common outlet. The odour emission rate is an odour flow rate quantity of odour units that crosses a given surface per unit of time.

BS EN 13725 provides you with the method that helps you determine the odour concentration by dynamic olfactometry and odour emission rate. It gives a method where an odorous gas sample is determined by presenting a panel of selected and screened human panel members with that sample, varying the concentration by diluting with a neutral gas, to determine the dilution factor at the 50 % detection threshold.

BS EN 13725 provides data and guidance from a regulated stationary source (facility) to demonstrate compliance with certain regulatory requirements, and performance information to the facility operator so that corrective action can be taken, if necessary.

Overall, with BS EN 13725 you can be ensured that the products consistently meet and exceed quality assurance targets.