Guidance

MCERTS: requirements for installing and using event duration monitors

Published 31 March 2023

Applies to England and Wales

MCERTS standard specifying the minimum requirements for installing and using event duration monitors (EDMs) required by an environmental permit.

The Environment Agency set up the monitoring certification schemes (MCERTS) to provide guidance on the standards you must meet to monitor emissions that affect the environment.

1. Installations this standard applies to

1.1. This standard applies to installations with an Environment Agency or Natural Resources Wales environmental permit which requires them to install an MCERTS certified event duration monitor at one or more of the following locations:

• a waste water overflow to storm management system at a waste water treatment works
• a last in line overflow
• a sewage pumping station

The permit will also require the operator to collect and record the monitoring data produced.

This standard can also apply to other EDMs, if requested by an operator.

1.2. This MCERTS standard specifies the minimum requirements for installing and using EDMs required by a permit.

It describes the inspection and certification procedures. It also provides quality assurance procedures to make sure that EDMs are correctly installed and maintained.

This standard covers the requirements for the:

• certification process (section 2)
• installation and performance (section 3)
• management system – to make sure EDMs continue to perform effectively (section 4)

1.3. In this standard, the term EDM means a system designed to detect and record that a sewer storm overflow is operating.

An EDM may be:

• a device directly installed to detect an overflow event
• an alarm mechanism on a level measurement system
• a status signal from an overflow pump, penstock or valve
• some other system designed to detect an overflow event

The EDM system will include sensors, electronics, wiring and any other equipment needed to detect and record a discharge event.

1.4. This standard has prescriptive elements that are mainly based on recognised documents such as British and international standards. These are supported by the professional judgement of MCERTS inspectors when they inspect flow monitoring arrangements.

1.5. The assessment of whether an event duration monitoring system complies with this MCERTS standard is based on both an:

• inspection of monitoring arrangements – by MCERTS inspectors
• audit of the supporting management system – by MCERTS management system auditors

If the assessment shows that the monitoring system has met the standard, CSA will issue an MCERTS inspection certificate.

2 How this MCERTS standard operates

CSA (CSA Group Testing UK Limited) operates the scheme on behalf of the Environment Agency and Natural Resources Wales.

CSA appoint MCERTS inspectors after assessing them against the MCERTS standard MCERTS: competency standard for MCERTS inspectors and assistant inspectors – effluent flow monitoring. Passing this assessment means CSA considers the MCERTS inspector is competent to assess the installation of EDM equipment.

Management system auditors shall work on behalf of a UKAS accredited certification body, or for one accredited by an accreditation body that has signed the International Accreditation Forum multilateral recognition agreement. Certification bodies should have this MCERTS standard included in their scope of accreditation.

You can find contact details for MCERTS inspectors on the CSA website.

2.1. The site inspection and management system audit

2.1.1. The operator chooses an MCERTS inspector from the list of service providers on the CSA website.

2.1.2. The MCERTS inspector inspects the EDM installation and prepares an inspection report. The MCERTS inspector provides the operator with a copy of the inspection report.

2.1.3. The MCERTS inspector shall use on-site and other evidence to make sure that the EDM installation is being satisfactorily maintained. Installations with, for example, restricted access shall have specific maintenance procedures detailing how maintenance can be carried out. CSA cannot issue an MCERTS inspection certificate unless there is evidence that the installation is being maintained.

2.1.4. The operator contacts CSA or an alternative accredited certification body to arrange a management system audit.

2.1.5. The MCERTS management system auditor assesses the management system requirements relating to event monitoring and produces an audit report.

2.2. Applying for certification

2.2.1. If the MCERTS requirements are met, the operator can apply to CSA for an MCERTS inspection certificate. The MCERTS inspector can apply on behalf of the operator.

2.2.2. The application must include the MCERTS inspection report, the MCERTS management system audit report, and the appropriate fee.

2.3. Review and certificate issue

2.3.1. CSA reviews the evidence included in the application. Provided the MCERTS requirements are met, CSA issues an MCERTS inspection certificate to the operator. MCERTS inspection certificates are valid for 5 years from the date of the initial site inspection.

2.3.2. CSA will only issue an MCERTS inspection certificate if all the relevant requirements of the MCERTS standard have been met. The date on the MCERTS inspection certificate shall be the date on which the EDM installation was inspected.

2.3.3. The MCERTS certificate may be withdrawn or suspended if the operator has not paid (as per the contract terms) for the:

• MCERTS inspection report

• MCERTS management system audit report

• certificate (refer to 2.2.2)

2.4. Surveillance and reassessment of the management system

2.4.1. To maintain certification throughout the certification period, the operator’s management system shall be subjected to periodic surveillance. To support ongoing MCERTS compliance, a surveillance audit will cover (at least) the main areas in these sections:

• 4.5
• 4.9
• 4.10
• 4.12
• 4.13
• 4.14

The first surveillance visit will take place approximately 12 months after the initial assessment. After this, CSA will determine when the next surveillance visit will be, following the auditor’s recommendation and based on the audit findings.

2.4.2. If an operator wishes to challenge the audit findings or the recommended surveillance interval, they should contact CSA.

2.4.3. The management system is reassessed every 5 years. The reassessment audit will be similar to the initial assessment.

2.5. Installations that fail site requirements

2.5.1. If an EDM system fails to meet the MCERTS requirements, operators shall carry out remedial work. The MCERTS inspector shall provide guidance on the remedial work needed to make the EDM installation conform with MCERTS requirements.

2.5.2. On completion of the remedial work, the MCERTS inspector conducts a reinspection to confirm that the EDM now conforms with MCERTS requirements.

2.5.3. Provided the MCERTS requirements are met, the MCERTS inspector gives the operator an MCERTS inspection report confirming that the EDM now meets the MCERTS requirements.

2.5.4. The operator can then apply to CSA for an MCERTS inspection certificate.

2.6. Management systems that fail requirements

2.6.1. If the MCERTS management system auditor identifies significant deficiencies in the operator’s management system, they will record and present these to the operator during the audit. The operator shall be given an opportunity to address the deficiencies and provide evidence of corrective action. Further audits may be required to collect evidence that the operator has resolved the deficiencies.

2.6.2. Provided the management system meets MCERTS requirements, the auditor provides the operator with a report confirming this is the case.

2.6.3. The operator is then able to apply to CSA for an MCERTS inspection certificate.

2.7. Dispensations

2.7.1. A monitoring system may fail to comply with MCERTS requirements in a relatively minor way, but the cost of immediate rectification would be high. In these exceptional cases the operator can apply for a dispensation agreement. The application shall be reviewed by the regulator and confirmed by CSA. If a dispensation agreement is confirmed, CSA will record the decision and issue an MCERTS dispensation certificate.

2.7.2. A request for a dispensation agreement should be sent to the regulator with the following information:

• a copy of the MCERTS inspection report, which shall state why the monitoring system does not meet the MCERTS requirements and suggest what remedial work is needed to correct the situation
• a cost and benefit analysis business case for the recommended remedial work, or any alternative improvements, with a timetable for the work
• any other relevant information to support the application
• any additional information requested by the regulator

The regulator will review the information provided. It will consider the:

• technical justification
• impact on the permit requirements and local environment
• other relevant information

2.7.3. The regulator may need to discuss the matter with the MCERTS inspector before making a decision.

2.7.4. The regulator and the site operator will discuss the options and plans for remedial work including a timetable for completion.

2.7.5. If the regulator agrees with the request, the operator then makes an application to CSA which shall include:

• the most recent MCERTS Inspection report
• evidence that a dispensation has been agreed by the regulator
• a timetable for any remedial work
• evidence that the MCERTS management system requirements have been met
• the associated fee

2.7.6. When they receive the application, CSA will review the evidence submitted and confirm the dispensation agreement with the regulator. They will then issue an MCERTS dispensation certificate valid for the agreed timetable, up to a maximum of 5 years from the date of the site inspection. The certificate will refer to the dispensation agreement.

2.7.7. If the regulator agrees to a dispensation, the operator must still maintain a management system (section 4). The management system shall be subject to periodic surveillance.

2.7.8. Dispensation agreements are not a permanent provision and the regulator expects that operators will resolve the problem as soon as reasonably practicable. If a dispensation certificate needs to be extended at the first recertification, the operator shall provide the regulator with an explanation and justification of why they have not resolved the problem in the preceding 5 years. Normally, the regulator will only allow one extension of a dispensation.

2.8. Recertification

2.8.1. An MCERTS inspection certificate is valid for 5 years. Sites shall undergo recertification within 5 years of the previous MCERTS certification. The monitoring system should meet the MCERTS requirements before the current certificate expires, which includes a reassessment of the management system.

2.8.2. An EDM can be reinspected up to 12 months in advance of the MCERTS inspection certificate renewal date. If it passes the reinspection, then a new certificate can be issued to run for 5 years from the expiry of the old certificate.

2.8.3. If an EDM fails the reinspection, the operator shall carry out remedial work as soon as is practicable. A further inspection by the MCERTS inspector is needed to confirm that the EDM now meets the MCERTS requirements.

2.8.4. If there are any changes to the event duration monitoring arrangements that could affect the measurement uncertainty, recertification shall be required as soon as is practicable.

3. Selecting and installing EDMs

This section describes the requirements for selecting and installing instruments. It describes the role of the MCERTS inspector and gives guidance on the attributes of an EDM installation they should assess.

3.1. Instrument and site selection requirements

3.1.1. EDMs may be placed at any location that is appropriate to measure the required events. The operator shall select the most appropriate location for the EDM monitor. This will depend on site configuration, ease of access and other factors, including the requirements and guidance contained in this document.

3.1.2. The operator shall position and set the EDM to record the entire duration of any discharge to the storm management system.

3.1.3. In locations which are known to be prone to surface foam, operators shall use EDMs which detect the true water surface.

3.1.4. It shall be possible to access the EDM safely for maintenance, inspection and verification. The operator shall locate the EDM where it will not inhibit the operation, cleaning and maintenance of the discharge structure or pump.

3.1.5. The regulator allows operators to select an EDM system that they believe is best suited to their situation. The EDM may be:

• a device directly installed to detect an overflow event
• an alarm mechanism on a level measurement system
• a status signal from an overflow pump, penstock or valve
• some other system designed to detect an overflow event

Any directly installed device or level sensor needs to be fit for purpose and comply with performance requirements specified in the relevant MCERTS standards.

Any new or replacement EDMs installed after 1 April 2025 should either:

• hold product certification under MCERTS: Performance standards and test procedures for event duration monitors
• be the level sensor component of a flowmeter certified as Class 1 under MCERTS: Performance standards and test procedures for continuous water monitoring equipment part 3: water flowmeters

An exception can only be made if there is no suitable MCERTS certified product available for the specific installation and the regulator agrees this in writing.

A list of MCERTS certified products is available from CSA.

3.2. Installation and performance requirements

3.2.1. The EDM shall indicate that a discharge event is occurring. Where an EDM activates when the liquid level exceeds the lowest point at which a discharge shall occur, then this will happen with an uncertainty of ±5mm or better.

3.2.2. An EDM which also provides a measurement of liquid level shall detect or indicate the level with an uncertainty of ±5mm or better at the discharge level.

3.2.3. The EDM shall indicate the discharge status (discharge or no discharge), or the water level (or both) at 2-minute intervals, or as specified in the permit. The status shall be recorded and available. Each value shall be time and date stamped.

3.2.4. The operational status of the EDM (operational or not operational) shall be recorded and available at each 2-minute interval or whenever a discharge starts and stops. Each value shall be time and date stamped.

3.2.5. The operator shall set EDM, logger and telemetry settings to reduce the likelihood of recording false positive and false negative events due to turbulence and standing waves.

3.2.6. Where a discharge event is caused by flow over a weir, the location of the EDM sensor should minimise the effect of any turbulence caused by the flow over the weir.

3.2.7. If a sensor is located upstream of the weir, the distance upstream should be no more than 5 times the height of the weir. (The height of the weir is measured from the channel bottom to the weir crest.)

3.2.8. If there is a side weir on both sides of a channel, either a single sensor should be located on the centreline (±10% of the channel width) of the channel, or a sensor should be fitted to each weir.

3.2.9. The operator shall make sure the EDM is robustly mounted so it is secure, stable and free from vibration.

3.2.10. Swinging or hinged mounting arms should not be used unless they are necessary to allow maintenance to take place if the transducer cannot be safely accessed from the side or from a walkway. Where they are used, they shall include a mechanism that makes sure the support relocates into the same position. The arm shall be tightly secured in place when in the measuring position, to make sure any movement is minimal when the EDM is operational.

3.2.11. Where appropriate, the operator shall make sure the EDM sensor is protected from damage due to debris carried in the flow.

3.2.12. For a non-contact EDM, operators shall make sure the measurement path from the sensor face to the water surface is kept clear of obstacles which may cause false reflections, such as sample hoses and ladders.

3.2.13. When locating the sensor, operators shall take into account the dead band of an ultrasonic sensor so that the minimum distance from the sensor face to the overflow level is at least equal to the dead band, plus an additional 50mm.

3.2.14. For EDMs that require a way of compensating for changes in the speed of sound through air due to temperature variation, the operator should install the thermometer in a suitable location, according to the manufacturer’s instructions.

3.2.15. Some types of EDM sensor require reference to a datum. This may be the bottom of a channel or tank, the weir crest or some other fixed point. During commissioning of the EDM the operator shall set this datum as accurately as possible. Uncertainty in the datum setting shall be included in the overall assessment of the capability of the EDM to detect discharges within the requirements of this standard.

3.2.16. The operator should set the response time of the EDM to a suitable value considering the likely rate of change of the water level and the required recording interval.

3.2.17. The operator shall install sunshields for all non-contact EDMs operating on ultrasonic principles that are exposed to direct sunlight.

3.2.18. If a non-contact EDM is located where it is likely to become submerged, and cannot reliably transmit a signal and receive the reflection from the water surface, the operator can use one or both of these options. They can fit a:

• second, contact EDM to confirm that the water level is exceeding the overflow level
• submergence shield

A submergence shield is typically a cone that is attached to the sensor in a watertight way that traps an air gap below the sensor face as the water level rises. The bottom edge of the submergence shield shall be at least 50mm above the overflow level.

3.2.19. Operators shall place sensors installed in below ground chambers or wet-wells as close to the ground surface as possible (taking into account the maximum range and accuracy of the EDM). This is to make sure inspection and maintenance can take place easily. Where radio or cellular telephone network telemetry is used this will also maximise signal strength.

3.2.20. The logging, transfer and storage of data produced by an EDM should be robust enough to make sure that the operator is meeting permit conditions on completeness of data and ease of access by other interested parties such as the regulator.

3.2.21. The operator should fix electronics units, data loggers and telemetry units to a rigid and stable surface or permanent structure. They should secure excess cabling so it cannot interfere with the accurate operation of the EDM.

3.2.22. Where required, the operator shall follow any other installation guidelines for the EDM outlined by the manufacturer. The operator should protect the EDM from the impact of any environmental conditions, as recommended by the manufacturer. For example, many manufacturers of non-contact level sensors recommend protection from strong winds and rainfall in their signal path.

3.2.23. The operator shall install signs on (or next to) the EDM saying that it is an MCERTS certified regulatory device and should only be accessed by authorised personnel.

3.2.24. The operator shall make it possible for an authorised person, such as an Environment Agency officer or MCERTS inspector, to see the indicated discharge status on site. They can do this by:

• a display on the EDM
• a secondary display or indicator
• communication with the EDM using a mobile device

Connection and communication to an external device shall not interrupt the operation of the EDM. Any software or application required for this shall be available free of charge from the manufacturer.

If the operator is using a type A device which can only display a level reading, the level at which the discharge should occur shall be clearly displayed near to the level reading.

The EDM product standard defines a type A EDM as:

“an EDM which incorporates a water level sensor that provides a direct, or inferred, measurement of the water level up to and beyond the overflow level.”

3.3. The role of MCERTS inspectors and assistant inspectors

3.3.1. An MCERTS inspector is a technical specialist who can demonstrate considerable experience and expertise in assessing flow monitoring and EDM arrangements. An important role of the MCERTS inspector is to exercise professional judgement.

An MCERTS inspector is able to assess the potential effects of deviations in monitoring arrangements and estimate these as part of an uncertainty calculation. An MCERTS inspector can work alone or may supervise the work of others.

3.3.2. Section 3 of the Competency standard for MCERTS inspectors and assistant inspectors – effluent flow monitoring specifies:

• the competency requirements for MCERTS inspectors and assistant inspectors
• the duties that they may perform
• a code of conduct

3.3.3. An assistant inspector has specific technical expertise, primarily in measuring flow monitoring structures, or site process configuration (or both). They will have the competence needed to carry out these measurements unsupervised. Data and information recorded by an assistant inspector must be quality checked and controlled by an MCERTS inspector. The MCERTS inspector must apply any subsequent professional judgement.

3.3.4. It is not acceptable for an MCERTS inspector to simply do a desktop review of an inspection carried out by an assistant inspector. The MCERTS inspector must visit the site.

3.3.5. An MCERTS inspector must accompany and supervise individuals, for example, MCERTS trainees who are not appointed MCERTS inspectors or assistant inspectors.

3.4. Conformance assessment

3.4.1. The MCERTS inspector shall assess that the installation conforms and is operating to the requirements of this MCERTS standard. They will use recognised standard procedures and their professional judgement.

3.4.2. The MCERTS inspector shall establish that the monitor, and its installation and ongoing operation, are fit for purpose to provide the measurements required by the permit.

3.4.3. The MCERTS inspector shall establish that a monitor installed after 1 April 2025 has suitable MCERTS product certification. Or if it does not, that no suitably certified alternative product is available for the specific installation, and that the regulator has agreed its use in writing. The requirements of this standard shall still apply to the installation and ongoing operation of this monitor.

3.4.4. The inspection by an MCERTS inspector shall confirm that all of these apply, the:

• EDM has been installed and set up correctly
• EDM is operating within the performance requirements of this standard
• effects of any external influences have been assessed

3.4.5. The inspector shall exercise their professional expertise and judgement to assess whether the technical solution used to detect discharge events meets the requirements of this standard.

3.4.6. The MCERTS inspector shall assess the suitability of the monitoring installation by site inspection and examination of flow diagrams. The MCERTS inspector shall make sure that any diagrams provided are representative and accurate. The site inspection should include a walking audit of the site to confirm correct location of the EDM.

3.4.7. The MCERTS inspector shall assess the location of the EDM and the impact of hydraulic influences both upstream and downstream which could affect operation of the EDM.

3.4.8. The MCERTS inspector shall confirm that the site maintenance arrangements are adequate. They shall record any evidence of inadequate maintenance in the inspection report for investigation during the management system assessment. CSA cannot issue an MCERTS inspection certificate unless there is evidence that the installation is being satisfactorily maintained.

3.4.9. The MCERTS inspector shall carry out calibration or set up checks on the measuring instruments. These checks shall record the set-up program of the measurement instrument. This includes, for example, any zero datum, calibration reference plate setting, calculation method, programmed dimensions or range.

3.4.10. The MCERTS inspector shall confirm that any local display agrees with the monitor output.

3.4.11. The MCERTS inspector should confirm that any telemetry system is working correctly. They can do this by contacting the appropriate control room or data team and comparing the reported value to the local measurement. This might not be possible at some sites due to poor phone coverage.

3.4.12. The MCERTS inspector shall record whether the EDM meets the requirements of this standard. They shall use the information gathered during the inspection to assess the suitability and measurement uncertainty of the EDM. They will include this assessment in the inspection report.

3.4.13. The inspection report shall include:

• an assessment of the installation and setup of the EDM against the requirements of this standard
• a determination of the uncertainty (in mm) of the EDM to detect the beginning and end of discharge events
• an assessment of the adequacy of site maintenance arrangements
• an assessment of the adequacy of site verification checks
• details of physical checks carried out to assess the uncertainty of the EDM

The MCERTS inspector shall provide written justification if, in their opinion, the target uncertainty will still be achieved despite specific requirements being exceeded.

3.4.14. The inspection report should be sent to CSA to support an application for an MCERTS inspection certificate. The MCERTS inspector may make the application on behalf of the operator.

CSA will issue an MCERTS inspection certificate if all relevant requirements of the MCERTS standard have been met. The date on the MCERTS inspection certificate will be the date of the EDM inspection.

4. Management system

The audit of the operator’s management system checks that the operator has suitable maintenance procedures, record keeping and procedures for data acquisition and telemetry.

4.1. Establish and maintain a management system

The operator shall establish and maintain a management system for its event monitoring arrangements, to make sure that the performance requirements specified in section 3 are met at all times. Detailed guidance covering each of the management system requirements is available from CSA.

4.2. Contents of the management system

4.2.1. The management system shall include statements, information and documentation, as appropriate, covering:

• quality and environmental policy – section 4.4
• management responsibilities – section 4.5
• documentation – section 4.6
• operating procedures – section 4.7
• document control – section 4.8
• equipment inventory – section 4.9
• maintenance – section 4.10
• commissioning – section 4.11
• site changes – section 4.12
• verification – section 4.13
• data treatment – section 4.14
• corrective actions – section 4.15
• internal audit section – 4.16

4.3. Extension of MCERTS

4.3.1. This is an extension of MCERTS, based on the procedures described in Minimum requirements for self-monitoring of flow: MCERTS performance standard].

4.4. Quality and environmental policy

4.4.1. The operator shall establish and maintain a documented quality and environmental policy. They shall issue the policy shall under the authority of top management. A policy statement that complies with the requirements of ISO 14001, that includes a commitment to comply with applicable legal requirements, shall be considered to meet this requirement.

4.4.2. The operator shall make those responsible for MCERTS related operations aware of the policy.

4.5. Management responsibilities

4.5.1. The operator shall make sure that responsibilities and authorities for MCERTS are defined and communicated to all relevant personnel. Designated personnel, irrespective of other responsibilities, shall have responsibility and authority for:

• making sure they establish, implement, and maintain MCERTS management system procedures
• reporting to top management, and liaising with CSA and the regulator on the performance of the overflow EDM arrangements, including the management system and the need for any improvements
• making sure the requirements of the management system in relation to meeting the performance targets are communicated and understood

4.5.2. The operator shall make sure that persons with MCERTS responsibilities receive appropriate training and are competent. The operator shall keep appropriate records and documentation of training. Internal training and self-study may be acceptable but details of this should be included in the training records.

4.5.3. The operator shall maintain organisational charts and job descriptions of staff involved in event duration monitoring. Job descriptions shall include:

• job title
• description of duties
• responsibilities
• qualifications, training and experience requirements

4.6. Documentation

4.6.1. Management system documentation shall include the following:

• the quality and environmental policy referred to in 4.4.1
• an overview of the MCERTS management system and the EDM arrangements
• operating procedures

4.6.2. The current version of this MCERTS standard shall be accessible to all relevant personnel.

4.7. Operating procedures

4.7.1. The operator shall establish and maintain procedures and instructions as required by this MCERTS standard. Operating procedures can be in any form or type of media. The level of detail should be no more than is needed, based on the complexity of the organisation or the EDM arrangements.

4.8. Document control

4.8.1. The operator shall make designated, competent personnel responsible for authorising and maintaining management system documentation.

4.8.2. Controlled documentation shall not be amended without the authorisation of these designated competent personnel or their appointed deputies.

4.9. Equipment inventory

4.9.1. The operator shall maintain a list of major items of equipment and the location of each. A major item is defined as equipment that is critical to the validity of event duration monitoring, for example, the sensor and electronics.

4.9.2. The operator shall keep equipment records for each major item. The records shall contain details of the equipment, its unique identifying code and any relevant calibration and maintenance requirements.

4.10. Maintenance

4.10.1. The operator shall make sure that appropriate maintenance of the EDM installation is carried out. Equipment shall be maintained and serviced at pre-defined intervals (for example, according to manufacturers’ instructions or operating procedures) and whenever a significant deterioration is noticed.

4.10.2. The frequency of scheduled maintenance activities, such as removal of fouling, shall be supported by documented observations. The operator shall complete up to date maintenance records in a timely manner and keep them where they can be accessed. These records shall include any problems encountered, for example, due to adverse weather conditions.

4.11. Commissioning

4.11.1 The operator shall establish and maintain a procedure for commissioning replacement or modified EDM installations (such as a new monitor or associated instrumentation), to make sure that they continue to conform to the requirements in section 3.

4.12. Site changes

4.12.1. The operator shall establish and maintain a procedure to document any changes that could affect the EDM (for example, changes to manufacturing or effluent handling processes). A competent person shall assess the risk of these changes influencing the performance of the monitoring equipment. The operator shall maintain records of such assessments. The competent person shall determine whether the MCERTS inspection certificate has been invalidated.

4.12.2. If the competent person’s assessment indicates that the MCERTS inspection certificate has been invalidated then an MCERTS inspector shall carry out an inspection as soon as practicable.

4.12.3. If the competent person’s assessment indicates that the MCERTS inspection certificate has not been invalidated, the operator shall document their justification. They shall make this justification available for examination by the MCERTS management system auditor at the next audit.

4.13. Verification

4.13.1. The operator shall carry out appropriate verification between MCERTS inspections, over the entire certification period, to make sure that the monitoring equipment is operating satisfactorily.

4.13.2. Verification shall include at least one of the following methods:

• calibration (in a calibration laboratory)
• appropriate in-situ checks (such as reference plate for non-contact level sensors)
• comparison with a secondary device

4.13.3. Where the above methods are not possible, an alternative method is permitted. Any alternative method shall be agreed in writing with the MCERTS inspector. This can be documented in the site inspection report.

4.14. Data treatment

4.14.1. Where applicable, the operator shall include procedures for data treatment and telemetry in the management system. The operator’s management system shall define the maximum acceptable data treatment and telemetry error.

4.14.2. The management system auditor is not required to carry out data treatment and telemetry verification measurements, but is required to make sure that the:

• appropriate checks are specified in the operator’s operating procedures
• procedures are being implemented in a timely and appropriate way
• results are being recorded and analysed
• results are included in the overall assessment of the total uncertainty

4.15. Corrective actions

4.15.1. If an operator has not complied with this MCERTS standard or their operating procedures, a competent person shall instigate corrective action. A competent person, who may be different to the instigator, shall carry out corrective actions in a timely way. The action taken shall be proportional to the significance of the non-compliance and shall include action to prevent recurrence. The operator shall maintain records of any non-compliance and the action taken.

4.16. Internal audits

4.16.1. Internal audits shall be performed according to a defined schedule to verify that operations continue to comply with the requirements of the management system and with the current version of this MCERTS standard. It is the responsibility of the designated competent person to plan and organise such audits. They shall be carried out by trained personnel who are operationally independent of the activity to be audited. Personnel shall not audit their own activities, unless the operator can demonstrate that it will be effective.

4.16.2. The operator shall keep a record of the audit findings and any corrective actions arising from them. The operator shall make sure that they implement corrective action in a timely manner.

4.17. Conformance assessment – management system

4.17.1. The certification body conducting the management system audit shall be a UKAS accredited certification body, or one accredited by an accreditation body that is a signatory of the International Accreditation Forum multilateral recognition agreement. Certification bodies should have this MCERTS standard included in their scope of accreditation. The management system auditor shall work on behalf of an accredited certification body.

4.17.2. The management system auditor shall assess the operator’s management system to make sure it meets the requirements of sections 4.4 to 4.16 in relation to the event duration monitoring arrangements.

5. Status of this document

This MCERTS standard may be subject to review and amendment following publication. The latest version is available on the MCERTS page on GOV.UK.

CSA issues bulletins providing updates and additional guidance or instructions. These bulletins are available on the CSA website.

If you have any questions regarding the inspection process, please contact CSA at:

CSA Group Testing UK Ltd
Unit 6
Hawarden Industrial Park
Hawarden
DEESIDE
CH5 3US

Telephone: +44 (0) 1244 670 900

email: mcerts@csagroup.org