BS EN 15780-2011 pdf download.Ventilation for buildings Ductwork – Cleanliness of ventilation systems.
5.3 Design and handing over information
In the handing-over documents the cleanliness quality class, cleanliness criteria and measurement methods shall be specified, recommendations for cleaning methods and guidelines for reaching the points to be cleaned shall also be given.
The design information shall give consideration to the expected cleaning method. Where the system has been designed to be cleaned by wet cleaning methods, warning regarding conditions and restrictions of use should be given. For example wet methods are applicable only where ducts are sufficiently moisture-tight, internal surfaces are smooth, and slope and drainage arrangements have been provided so that fluid and contaminant can be evacuated.
A sufficient number of access doors shall be provided in the ductwork. Additionally special care shall be taken regarding obstacles to cleaning such as dampers, sound attenuators etc., which are mounted in the ducts. In many cases additional access doors are needed after or before such obstacle, which then can be cleaned carefully. Requirements for location of and distance between access doors are presented In EN 12097 and EN 13779.
5.4 Determination of cleaning interval
The cleaning interval shall in principle be defined by reference to the cleanliness or dirtiness of the system. Cleanliness or dirtiness shall in the first instance be assessed visually and this may be confirmed by means of measurement — see Annex A.
The inspection interval to determine the need for cleaning may be defined in the system documentation in order to assist with maintenance planning or design considerations related to cleaning methods.
NOTE Further guidance can be found from REHVA and EVHA Guidelines and also from national guidelines, e.g. VDI 6022 or HVCA TR19.
5.5 Assessment of the result of cleaning
Methods for assessment of the need for cleaning can be also applied for assessment of the result of cleaning.
The preferred method of post-clean verification is given in Annex A.
See also 7.1.
6 Methodology
If the components are certified for cleanliness or the cleanliness after production is otherwise verified. and it the cleanliness instructions are properly documented, the commissioning may be reduced to checking the documentation and spot checking of the system cleanliness (compliance with the documentation). See also 6.2.2.
The methods applied for objective measurements and verification need to be consistent so that the result of inspection is acceptable and give reliable grounds for decision making to order cleaning work of the system when needed. Verification after cleaning is needed for quality control of the cleaning work, and to verity the cleaning result.
NOTE ‘I Annex H describes the preferred method of objective measurements.
NOTE 2 An example of acceptable levels of cleanliness (or dirtiness) Is explained In Annex F.
Objective methods are needed if any guidelines or demands on cleanliness are set in official or in voluntary documents. The methods to evaluate the cleanliness vary, and thus target values given for the cleaning shall be accompanied by a description of the measurement method. Certain rare visible signs like visible microbial growth are enough to reveal the need for cleaning. For systems (consisting dust with less potential health risks) affected by dust the visible signs are not so clear and evaluation of the need by measurement may be needed to find out whether the ventilation system should be cleaned or not. Suspected instances of hazardous dusts such as asbestos and radiological materials need specialist investigation and should be dealt with separately.
6.2 Assessment of the need for cleaning
6.2.1 General
Assessment of the characteristics of the contamination of the system is important in order to define the cleaning method to be used.
System components are considered to be polluted when visual inspection and analytical verification give evidence of unacceptable dust level, microbial or other contamination. Assessment will be carried out through inspection. Dust accumulation, the type of pollutants, such as bacterial growth should determine the need for cleaning, deaning methods to be used and the required environmental controls.
Elements to be inspected for cleanliness start from the outdoor air intake and should include at least:
— Air Handling Units (AHU’s). AHU’s assessment should include all their components and sections:
outdoor air intake, any mixing sections fan section, filters, plenums, heating and cooling coils, condensate trays. sound attenuators, heat recovery section, and humidifier section including droplet eliminators;BS EN 15780-2011 pdf download.