Humidification & Water Systems

Health & Hygiene

Health & Hygiene

Any cold water humidification or fogging system must maintain a high level of cleanliness and meet strict UK Health and Safety Executive (HSE) codes of conduct (L8)

Over the last fifteen years, Norman Pendred and Company have researched, developed and utilised a variety of technologies to filter and de-mineralise fresh drinking water to manage micro-organism (bacteria, fungi, mould, spores, viruses, parasites) levels within their systems, including Legionella. We have developed and operate a number of patented hygiene management systems.

This design combined with regular servicing and maintenance provides a hygienic and efficient system.

Water Purification. Only fresh potable (drinking) water should be used. De-mineralisation minimises the build up of lime-scale in equipment, in a cold store or on retail food display counters. The chemical content of the water is also controlled through water filtration.

Reverse Osmosis. RO is the process in which water is forced by pressure through a semi-permeable membrane. Water passes through the membrane while the dissolved minerals and particulate materials are too large and are removed.

Filtered water fed into the RO membrane is separated into two streams:

  • Permeate or ‘Product Water’ passes through the membrane.
  • Concentrate or ‘Brine Water’ which cannot pass through the membrane, retains the rejected ions, organics and suspended particles.

Unlike simple filtration where contaminates are held within or on the surface of a filter, in an RO, solids are swept away with the concentrate stream, eliminating frequent membrane filter changes.
In domestic or low quality RO systems the ratio of feed water, which is recovered as permeate, typically ranges from 1-4. That is 1 part of product water for 4 parts of brine water.

Although there is little wrong with brine water, except that it contains a much higher content of dissolved solids, it is often flushed to drain. Pendred systems do not do this. Our technology enables the system to produce 2 parts of product to 1 part of brine in the summer and 1-1 in the winter. If a water softener is installed before filtration we can double this to 4-1 in the summer and 2-1 in the winter. We also recover the brine water for re-use else where on the facility wherever possible.

Air filtration and Purification. It is very important that clean air is used in Air Spray Humidification or Fogging Systems. The removal of dirt, dust and bacteria from air can be achieved in a number of ways.

The ambient air in food processing plants and retail stores can be affected by the type of food prepared or displayed. Meat maturation rooms, meat processing plants and butchery departments in retail outlets pose the greatest challenge.

Integrated Systems to manage and control bacteria etc. All moisture maintenance systems use water and the bacteriological content of the water must be managed. This is achieved through technologies such as Ultra Violet Radiation, Oxidation by Ozone and Chlorine-based disinfectants. In addition, microbial growth suppression is achieved through maintaining low water temperatures and its use within a refrigerated environment.

There are a number of technologies used to achieve the necessary levels of hygiene. The method applied varies depending on the system in operation.

PENDRED offer the following water treatments:

  • Simple particle filtration to remove solids from city drinking water.
  • Activated Carbon filters to remove chemicals from city water.
  • Softening to exchange calcium ions with sodium ions that do not form hard scale.
  • Reverse Osmosis de-mineralisation to reduce the build up of limescale in equipment.
  • Chemical and non-chemical disinfectant dosing to seek out and destroy bacteria from air, water and equipment.
  • Ozone to seek out and destroy bacteria in air, water and equipment.
  • Low Temperature Ultra Violet Radiation (LTUV) to kill any bacteria left in the product water or the air used to deliver the moisture.

Since 2010, Pendred have researched chemical and non-chemical disinfectant fogging, misting and spraying. Pendred’s own Scientific Research and Development department have worked closely with research bodies such as universities; and food safety departments of food growers, processors and retailers. Interest in Pendred systems and investment in the development of cutting-edge, innovative hygiene solutions from the UK government Department for Environment, Food and Rural Affairs (DEFRA) has accelerated developments (improving hygiene, reducing the quantity or need for chemicals by researching natural disinfectants).


Useful Links:

HSE L8 Legionnaires’ Disease: Approved Code of Practice –

Humidity Group Code of Best Practice – 1: Cold Water Humidification Systems

Humidity Group Code of Best Practice – 4: Commissioning and Planned

Minimising the Risk of Legionnaires Disease pdficon_large