Problems With Your Air?

The team at Red Dragon Ltd discuss the problems of contaminated plant and instrument air, and how this can be addressed.

Plant or instrument air is often viewed as a clean resource and it can be, but in practice is often contaminated due to insufficient filtration, corrosion from within the ring main system and ingress through leaks and breather ports.

Installation instructions will state that a valve, actuator etc. must be used on ‘clean, dry and unlubricated air’ but in many plants, the air quality is governed by the compressor/filter/dryer maintenance regime (or lack of) without the benefit of any objective measurement at point of use. Pneumatic positioner requirements will often state a minimum filtration level to avoid failure but this doesn’t take into account oil vapour/aerosol levels or the water content of the air expressed as humidity or dew point, both of which could affect reliability of the unit.

Industries such as Food and Pharmaceutical take a rigorous approach to air quality because it comes into contact with their end product and as such, measure in accordance with ISO 8573 which classifies levels of water, oil, particle and even microbial contamination. Measurement of air quality and maintaining adequate records is therefore vital for them but does it matter in engineering or manufacturing?

Oil is a common contaminant in air systems and will be released to the atmosphere through any pneumatic valve exhaust port, air mover or leaking joint. What would happen if one of your team was degreasing a valve prior to it being installed on an oxygen line, using a compressed air blow gun to remove the solvent and the air was poorly filtered or worse, lubricated? If it missed ultraviolet inspection and put in service, this valve could be a potential fire risk. Have you ever been in a plant where every surface is covered with a sticky residue from oily air? It’s not good for operators’ lungs either.

Do you see early failures and warranty return claims with no obvious cause? Maybe it’s not mechanical failure through manufacture or operation but brought about through contaminated air. Elastomer diaphragms and seals can fail early when oil is present in the air stream. Oil will capture dirt particles and cause pilot orifices to block. Entrained rust particles can be abrasive. Water vapour in the air can promote internal corrosion. Are you told that it was only being used on clean instrument air? Can that be verified? Can you see a copy of the most recent audit?

Poor compressed air quality can have a significant impact on a business through many factors including increased maintenance costs, increased energy consumption and reduced product quality. Only by measuring the delivered air quality can you be sure of whether it is as clean as expected. This is an excellent means to guide planned maintenance to resolve air plant issues before they become real problems that can affect operations or customers.

If there is an agreement with a contractor to manage the compressed air plant, ask them to audit the air quality around the plant to verify that the delivered air meets the standards claimed. Failing that, hire or buy the necessary equipment to perform your own audits or where it is of particular concern, consider installing a continuous measurement system.

At Red Dragon, we can help with portable or fixed measurement, monitoring and analysis solutions for air/gas consumption and quality. Is it time to consider if your air quality is good enough and give us a call?

Red Dragon Ltd
Tel: 01443 772 500
Web: www.reddragonvalves.co.uk
Email: sales@reddragonvalves.co.uk

Published: 24th November 2015