Velocity Manometer

The velocity manometer is an extremely useful tool mostly used during our damp / condensation surveys. This tool is used to establish the performance of mechanical ventilation systems and measures the rate at which air is drawn into the fan. Building regulations specify the minimum rate which air should be drawn through a mechanical fan in a domestic kitchen or bathroom which is 15 ltrs per second. Whilst most fans can achieve this under factory test conditions when installed the performance of the fan can be reduced dramatically, through poor installation or positioning. An inefficient fan in major moisture producing rooms like the kitchen or bathroom can significantly increase the risk of damp, condensation and mould problems not only in these rooms but other adjacent rooms within the property.

During our damp surveys the velocity manometer is an invaluable tool to measure the performance of existing domestic ventilation systems which enables us to assess if the mechanical fan is working effectively. Simply pulling a cord and hearing a noise does not necessarily mean the fan is working or is working effectively, the poor performance of the fan maybe a contributory factor to the cause of your problem, hence why at Dryfix we test and inspect everything to prove our findings.

The effectiveness of a fan can be reduced dramatically dependent upon its positioning, installation, length of ducting to atmosphere, quality of ducting and number of angles/bends within the duct. Over the years we have surveyed countless properties suffering with mould and condensation problems which have been the result of poor ventilation. The velocity manometer is the only effective means of testing the performance of mechanical ventilation systems and provides us with a rate at which the fan is exhausting air in cubic feet per minute and litres per second. Understanding the airflow rate allows us to clearly see how well the fan is performing in correspondence to the building regulation minimum requirements.

It is not uncommon for fans to become clogged with dirt and debris collected from the air reducing its performance, fans need to be regularly cleaned. Long lengths of ducting to atmosphere, corrugated ducting and multiple bends reduce the air flow rate which can often result in condensation forming within the duct meaning the fan becomes completely useless (a video of our technicians removing water from a water logged ventilation duct is show below). Positioning of mechanical ventilation is often over looked as the location is also crucial. Fans should be positioned where they will be most effective and where the ducting length (if required) will be kept to a minimum (Read our blog for further advice on ventilating your home properly).

Modern fans also have multiple functions such as humidistats, over run timers and humidity sensors and choosing the right function for the fans requirement is essential.

If you're experiencing problems with damp, condensation and mould and require a survey, choose a company that invests in its equipment, systems and staff but also a company who cares to diagnose and repair your problems correctly first time.

At Dryfix our surveys are only undertaken by experienced and qualified remedial surveyors who hold the C.S.R.T qualification. This recognition is only awarded by the Property Care Association (PCA) formally known as the BWPDA British Wood Preserving and Damp Proofing Association our industry body. This qualification proves our surveyors have been independently examined and tested proving their extensive knowledge and expertise.

Our surveys are undertaken in accordance with relevant British Standard Codes of Practice and our surveys complied in comprehensive, detailed and edited reports. Our reports include edited pictures, detailed specifications, recommendations and costing's along with category damage ratings to assist your understanding of the urgency of any problems identified. Our reports are available in both printed media and/or converted into secure electronic Portable Documents (PDF) for email.

For further information or free advice please do not hesitate to contact us on 01904 791388

Specialist Services

Dryfix Preservation Ltd | Head Office: Unit 12, Pyramid Court, Rosetta Way, York, North Yorkshire YO6 5NB.