Solvent Emissions (Scotland) Regulations 2004: guidance

Guidance on the Solvent Emissions (Scotland) Regulations 2004

11. GUIDANCE ON MONITORING REQUIREMENTS

11.1 Annual Demonstration of Compliance

The SED places an obligation on Member States to ensure that all installations subject to the SED, supply appropriate information to demonstrate compliance with the SED at least once per year

Operators will be required to provide SEPA with solvent management plans (SMP) on an annual basis to demonstrate compliance. In addition the SMP will require the operator to report on the solvent consumption of the activity.

Where the solvent consumption falls below the thresholds specified in the SER 2004, then the installation is no longer subject to the requirements of the SED and the SER 2004 no longer applies.

11.2 Continuous Monitoring Requirements

Continuous monitoring for compliance must be fitted where:

• abatement equipment is fitted; and

• at the final point of discharge from the abatement equipment there is an emission of more than an average of 10kg/hour of total organic carbon

This can include surrogate measurements such as monitoring the operating temperature or carbon monoxide emissions from thermal oxidisers.

Where an activity is also prescribed under PPC, the BAT requirements identified in technical guidance notes can require the continuous monitoring of surrogate parameters, even if the final release is less than an average of 10kg/hr of total organic carbon.

11.3 Compliance Criteria for Continuous Measurements

Where continuous monitoring is applied the emission limit values (ELVs) shall be considered to be complied with if:

• none of the averages over 24 hours of normal operation exceeds the ELVs; and

• none of the hourly averages exceeds the ELVs by more than a factor of 1.5.

11.4 Periodic Measurements

Where continuous monitoring is not a requirement, periodic measurements of solvent emissions must be carried out at least annually. At least three measurements must be obtained during each measurement exercise. The sampling time will be dependent on the operation of the particular activity and expected VOC loading. Initially the total VOC emission profile should be determined over the period of time that the process is operating to identify peak emissions.

Sampling should be conducted to cover the period of peak emissions. The sampling period should be agreed with the operator based on the emission profile and the minimum sampling time in the method used. Compliance shall be assessed based on a minimum of three samples and the hourly average must not exceed the ELV by a factor of 1.5.

11.5 Standard Monitoring Methods

The European standard method for measuring VOC as carbon is:

CEN 13526: "Stationary Source Emission Determination of the Mass Concentration of Total Gaseous Organic Carbon at High Concentration (20 to 500mg/m3 VOC) in Flue Gas Continuous Flame Ionisation Method."

This method involves extraction of a gas sample through a heated line to avoid condensation losses into a heated flame ionisation detector (FID). The FID is calibrated with propane or methane and gives a direct reading as parts per million per volume propane or methane equivalent VOC which can then be converted to mg/m3 carbon at standard temperature and pressure (STP, 273.15 K, 760mmHg) using the mass of carbon in the calibration gas and the molar volume 22.4 litres at STP. For further advice on monitoring operators should contact the local SEPA office for assistance.

11.6 Addition of Cooling or Dilution Gases

Gas volumes can be added to the waste gas for cooling or dilution purposes, where technically justified. However any such addition shall not be considered when determining the mass concentration of the pollutant in the waste gas.

11.7 Compliance Criteria for Periodic Measurements

In the case of periodic measurements the ELVs shall be considered to be complied with if, in one monitoring exercise:

• the average of all the readings does not exceed the ELVs; and

• none of the hourly averages exceeds the ELV by more than a factor of 1.5.

There is no guidance on the length of a monitoring exercise, but in the case of batch operations it would be reasonable to assume that the monitoring exercise would cover one batch with at least one of the three measurements required being made during a period when the maximum VOC concentration in the waste gas would be expected.

11.8 Verification of Compliance Following a Substantial Change

Following a substantial change to any activity compliance should be reconfirmed. During commissioning, compliance should be assessed on the same basis as is applied annually, i.e. when the substantially changed part of the plant is running at normal operating parameters.