It is well known that those who work with certain types of materials and products in the workplace can be at risk of ill-health due to the dust particles they emit.
Here are 5 facts about dust, however, that you may not be aware of.
1. It’s Not Just Your Lungs That Are at Risk
Most people are aware that breathing dust can cause all sorts of health issues, such as asthma and lung cancer. But did you know that dust particles can also be swallowed and get into:
- the digestive tract where it can cause irritation,
- the blood stream where it can damage other organs and tissues,
In addition, dust particles can get:
- into the eyes where they can cause eye damage or irritation, and
- onto the skin where they can cause ulceration and irritations, which can lead to dermatitis.
2. The Risks Are Greater Than You Think
Some types of workplace dust are more harmful than others. Hazardous dusts which are common in some industries include:
- Asbestos – asbestos still kills around 5,000 workers each year (more than the number of people killed on the road)
- Flour – flour dust and enzymes containing additives such as amylase are the second most common cause of occupational asthma.
- Grain – grain dust (from barley, oats, wheat etc.) also contains contaminants, such as bacteria, fungal spores, insect debris and pesticide residue!
- Silica – silica dust is released when stone, bricks or concrete, are cut or broken. In June 2019, the Health & Safety Executive HSE announced it would increase its testing of dust levels at construction sites.
- Wood – carpenters and joiners are four times more likely to get asthma compared with other UK workers because of wood dust.
3. Not All Dusts Have a Workplace Exposure Limit
Some dusts have COSHH Workplace Exposure Limits (WELs). WELs provide a guide for employers for controlling exposure. So, for example, silica dust, which is particularly harmful to health, has a WEL of 0.1mg/m. Other dusts may not have a WEL but might still be hazardous. According to the HSE,
“A dust is considered to be a substance hazardous to health under COSHH if it is present at a concentration in air equal or greater than 10mg/m3 (for inhalable dust) or 4mg/m3 (for respirable dust) as a substance hazardous to health.”
At this concentration or below, it is widely believed that any exposure to dust is to be kept as low as possible.
4. Some Dusts are Combustible
Certain dusts are combustible under certain conditions, as highlighted by the HSE. Wood and flour dusts are both combustible, as well as the dust from powdered ingredients, such as sugar custard powder, instant coffee and dried milk. Read more about combustible dust here.
5. You Can Be Fined If You Fail to Have Your Dust Extraction System Tested
Most employers are aware that they need to have the correct control measures in place to protect their workers from the hazards of dust – and there are various measures to suit different working processes. But if you use dust extraction systems (LEV) and don’t get them tested as per the requirements of the law, then you could be fined.
The law states that you must maintain your local exhaust ventilation (LEV) system so that it continues to provide the necessary protection. A thorough examination and test should be conducted at least every 14 months. Furthermore, you must keep a record of the test for at least 5 years. Information should also always be displayed on the LEV system to verify that it provides adequate protection.
For more information about HVDS dust extraction solutions, click here. To enquire about a dust extraction survey for your facility, please click here. To enquire about a thorough examination and test of your LEV system, contact us here or call us on 01785 256976.
Many modern food production environments need to cool their indoor air for two main reasons:
- For the comfort of employees
- To protect food safety
Not all cooling systems are the same. In this article, we look at evaporative coolers and why they provide the best solution for food manufacturers. We also introduce the HVDS COLD AIR F-Series and explain how it goes one step further in improving the quality of your air.
The Benefits of Reducing Temperature & Humidity
Heat and humidity can be an issue on site all year round but particularly during the summer months. Heat is well-known to affect productivity, health and safety and health. It can also result in reduced quality products and shorter shelf-life. The Chartered Institute of Building Services Engineers (CIBSE) recommends a temperature of 13℃ in factories for heavy work and 16℃ for light work.
Refrigeration-based Aircon versus Evaporative Coolers
Certain cooling methods, such as refrigeration-based air conditioning and mechanical ventilation have high capital and running costs. Evaporative coolers have low energy consumption rates, making them far more economical and efficient than other cooling methods. They also deliver important environmental benefits compared with air conditioners, which use refrigerant gases and release CO2 into the atmosphere, which can also contribute to global warming.
How Evaporative Coolers Work
Evaporative coolers work by passing air through wet filters. The air loses its heat due to the evaporation of the water. They also feature temperature and humidity controls, which optimise the environment. Evaporative cooling will also remove air from the product (deaeration) and this will delay bacteria growth, thus improving the quality and lengthening the shelf-life.
HVDS COLD AIR F-Series
The HVDS COLD AIR F-Series evaporative coolers go a step further still. As part of our research and development into new energy efficient clean air solutions, the COLD AIR F-Series now makes it possible to cool production areas, while ensuring quality of air. This is made possible due to the inclusion of an integrated air filtration system, available in G4 – F9 filtration class. COLD AIR F-Series adiabatic evaporative cooling ensures:
- environmental comfort
- energy efficiency
- quality of air
Industries that Would Benefit from COLD AIR F-Series
COLD AIR F-Series is suitable for:
- food industry
- pharmaceutical industry
- bottling plants
- warehousing etc.
In this article we look at how a typical and simple air handling unit works, including each of its component parts.
Where AHUs are Located
Air handling units (AHUs) can be found in the roof void, basement or floors of a building and will serve a specified area of that building. One building will therefore often have multiple AHUs.
The Purpose of an AHU
The purpose of an AHU is to clean, condition and distribute air around a building to help maintain good indoor air quality. This is important for any area or room that relies on having a continuous contaminant-free air supply.
How AHUs Filter Air
AHUs take air from outside the building and will filter the contaminants from it, heat it or cool it as required. AHUs then send the filtered air through the ductwork to distribute it to designated areas within the building. Most AHUs have an additional duct, which takes the used air (return air) out of the rooms and back to the AHU and to a fan that discharges it into the atmosphere. Some of the return air might be recirculated, which helps save energy.
A grill at the air inlet of the AHU prevents debris being pulled into the AHU. Dampers at the inlet regulate the amount of air entering or exiting the AHU. In a closed position they will prevent air entering the system and fully open they will allow air in and out.
Beyond the dampers are three sets of filters: pre-filters or panel filters that catch large dust particles, pollen and fungal spores, secondary filters or bag filters that catch smaller dust particles and microorganisms such as yeast, and finally a finer grade of filtration, such as HEPA filters, which are capable of catching microorganisms such as bacteria and viruses.
The grade of filters required depends on the application the AHU is serving (food production areas, clean rooms, such as in pharmaceutical and research facilities, hospitals etc.) Removing contaminants from the indoor atmosphere helps protect both processes and people. Pressure sensors measure how dirty the filters are. As filters collect dirt, the airflow through the filter media becomes restricted and this will cause a pressure drop as shown on the pressure sensors.
Regulating Temperature & Humidity
Heating and Cooling
Next, heating and cooling coils heat or cool the air, as necessary. The ‘set point temperature’ of the supply air is measured as it leaves the AHU and continues its journey into the ductwork. If the air is below the set point temperature, the heating coil will increase the air temperature, and if above, the cooling coil will decrease it to bring it to the set point.
For those buildings that need to control humidity, there will be a humidifier after the heating/cooling coils. A humidity sensor at the outlet of the AHU measures the amount of moisture (set point humidity) in the air. Where the air does not contain enough moisture, the humidifier will release steam or spray water mist into the airflow. Similarly, where the air contains too much moisture, the cooling coil will cause the moisture to condense and flow away and/or will reduce the air temperature. Where the air temperature dips below the supply set point, the heating coil can be switched on to raise the temperature again.
After the humidifier comes a fan. The fan pulls air in from outside and through the dampers, air filters and heating/cooling coils and into the ductwork. A pressure sensor across the fan will detect whether the fan is operating or whether there has been an equipment failure.
Next is the ductwork, which takes the air round the area the AHU serves. Some of the ducting brings the used air back from the specified area and into the return AHU.
A fan pulls the air from around the building in and then pushes it to outside the building. The return AHU also contains a damper, which stands at the exit of the AHU. This closes when the AHU switches off.
The Difference Between HVAC and AHU Systems
An AHU forms just part of the wider HVAC system. According to Mecart, a Canadian cleanroom manufacturer,
“There tends to be confusion between HVAC systems and AHUs. The air handler is the enclosure in which the air is heated, filtered and cooled. The HVAC system is the whole set up, which includes the AHU as well as the duct work, diffuser, HEPA filters, air return, and control and monitoring systems.”
HVDS provides and installs AHUs to the food industry. To discuss an AHU for your food production area, contact us on 01785 256 976 or get in touch here.
Our dust spares supply and installation business is booming. Customers want to be able to order the dust spares they need and have them fitted by trained engineers. At HVDS we do just that.
Our range of high quality state-of-the-art dust spares are designed for use in all makes and models of dust/fume/oil/mist extraction equipment. Our list of spares in stock here at HVDS includes LEV filter cartridges, filter socks and sleeves and pocket bags. We can also supply and fit, among other parts, filter regulators, damper motors, ducting, pressure gauges, valves and diaphrams and seals.
For your peace of mind, our accredited engineers will conduct regular LEV examinations and mechanical service inspections. HVDS LEV test engineers are P601 trained. P601 is the BOHS course for LEV engineers, which qualifies them for ‘Thorough Examination and Testing of Local Exhaust Ventilation Systems’. The LEV examination will highlight any maintenance requirements and the need for any replacement parts.
We have a dedicated dust extraction team. Jane Boon is our Dust Aftermarket Sales and Contracts Manager. Jane looks after our customers’ requirements for dust spares. She also coordinates engineer visits at a time to suit you. Jane says,
“We can offer you full system maintenance to keep you up and running and help you stay compliant at all times.”
HSE compliance is a major concern for manufacturing sites where dust, spray, mist, fume and oil is a challenge. Our service and dust spares are HSE and HSG258 compliant. Furthermore, maintaining your system it working at maximum efficiency will also help to prevent equipment failure and breakdown and reduce cost and energy use.
In food production sites, environmental air must be of a specified quality in terms of temperature, particle concentration and humidity. Additional controls are required for the manufacture of certain products and for high care production areas, in order to reduce the risk of contamination. Controlling the properties of indoor air can help to reduce the quantity and growth rate of micro-organisms in manufacturing areas and can reduce other particle content for maximum food safety. Airborne contaminants are removed by air filtration in the form of Air Handling Units (AHUs), and for the reasons outlined above, AHUs for the food industry differ from those for other applications, such as in residential or commercial environments. This article looks at the key design features of an AHU and ductwork for food production areas.
The food industry has a complex set of requirements for air management spanning food production, preparation and storage. Heating, ventilation and air conditioning (HVAC) systems can optimise elements of Indoor Air Quality (IAQ), such as temperature, humidity, odour and air distribution. Good IAQ has a major impact on product contamination, product shelf life and employee health.
“Properly designed air handling systems control airborne particulates and odours and minimise the risks to products from airborne contamination by infectious pathogens (e.g. Salmonella, Listeria, E. coli) and toxigenic pathogens (e.g. Staphylococcus aureus and clostridia) and spoilage micro-organisms (e.g. yeast, moulds, pseudomonads and lactic acid bacteria).”
Trends in Food Science & Technology 17 (2006)
Guidelines on air handling in the food industry
The design and maintenance of any AHU for use on a food production site, should be determined by the risks to product safety identified in the Hazard Analysis and Critical Control Points (HACCP) risk assessment and by the risks to product quality identified by the site’s quality control system.
Each area of a food production site will have different risks and, therefore, different needs with regard to air handling. Conducting a specific risk assessment to determine these risks and filtration requirements is recommended. This risk assessment template should be based on the BRCGS Food Safety Issue 8 guidelines. Contact HVDS for a ‘Risk Assessment for Positive Airflow’ template.
An AHU should be designed to accommodate the varying conditions of the following operational states:
Normal Production State
An AHU will distribute filtered air, with controlled humidity and temperature, into the production area at the required rate and will recirculate it at typically 85% recirculation through the system.
When no production is taking place, a specified overpressure or temperature is maintained by inputting filtered or fully conditioned air into the production area. The AHU will allow air to be recirculated at a very low rate, depending on a number factors (e.g. the heat load or loss from the system) to ensure a positive pressure is maintained.
During factory cleaning, it is necessary to input filtered fresh air into the production area via the ducting. This serves to a) maintain the overpressure, b) protect the filters from moisture damage, c) extract moisture in the air directly to exhaust (without recirculation).
AHUs for food production must be maintained with minimum production downtime and in such a way as to prevent production area contamination. Certain design features, for example duplication of some equipment or ducts, allow for efficient servicing.
Food production areas can be categorised according to risk. This risk ranges from low risk (ambient-stable, packaged foods) to high risk (chilled, fresh and ready-to-eat foods). The level of risk will determine the level of air filtration needed and this, in turn, will determine the design of the AHU, for example with regard to doors and inlet/outlet hatches.
The air system should slow or prevent the growth and ingress of micro-organisms and filter out the particles that carry them. Hygienic design of the AHU will also prevent the system itself becoming a source of contamination.
The air handling system plays a role in controlling contamination risk in medium and high care areas for certain processes and products, such as salads or sandwiches. And in a high risk production area, for example, in the manufacture of cooked meats, the air handling system plays a critical role in controlling microbiological risks. Filter grade selection is a vital part of ensuring the correct level of filtration in each type of production area. The following table outlines the recommendations for food industry filter application grades in low care, high care and high risk areas.
Pre-filter grade captures heavy or coarse particles, whereas final filter grade captures sub-micron particulate.
Note: The food industry should avoid at all cost using glass fibre bag filters due to their fibre release and carcinogenic characteristics.
A step up from high risk areas is aseptic processing where foods are packaged in sterile conditions to produce products that do not need refrigeration. Before production starts, the air handling system must be capable of being thoroughly decontaminated. The manufacturer of the aseptic system will usually specify what volume of sterile air must be maintained by the air handling system for a sufficient overpressure and air outflow. The air handling system will also have to accommodate the particular operating conditions of the aseptic room, such as draught etc.
Low humidity in certain production areas can cause food product water loss. Where maintaining humidity is a factor for food quality, there are ways of humidifying the air, such as with an atomising humidifier or a steam injection humidifier, which distributes steam directly into the airstream.
High humidity is linked to microbial growth and can cause dry food products to absorb moisture. Removing moisture from the air is therefore essential. A good practice is to cool the air by passing it through a cooling coil in the air handling system. This serves to cool the air and the condensed water from the air will then be drained away. The air is then heated back to operating temperature.
Dust, condensate, extracted product and bacteria can build up in the AHU and ductwork of an air handling system. It is therefore essential to have a regular sanitisation schedule in place.
To ensure maximum system hygiene and to avoid the various parts of the system themselves becoming a source of contamination, an air handling system for the food industry must be manufactured with hygienic components and designed to facilitate visual inspection and regular deep cleaning. For example, there should be doors and hatches at regular intervals along the ducting to facilitate both inspection and cleaning. Ease of cleaning will also significantly reduce any production downtime.
The type and frequency of a cleaning schedule will be determined by a number of factors, including the standard of hygiene required in any specific production area, the contaminant burden in the fresh and recycled air, air velocity etc.
2019 was a very busy and successful year for HVDS and 2020 will see us building on that growth. Here is what is in store for the company this year.
New Members of Staff
We welcome Christian Taylor, who joins our dust extraction team as Projects and Contracts Engineering Manager. Christian will be helping customers with new dust extraction system installations. For a new installation quote for your site, get in touch with Christian at firstname.lastname@example.org
As manufacturing sites continue to prioritise regular ductwork and flue extraction cleaning, we will continue to recruit engineers to our Hygiene Team. The team performs deep cleans of systems all over the UK to keep them energy efficient and audit compliant. To book your deep clean, contact us here or to enquire about a cleaning engineer role at HVDS, check our careers page here.
Our Food Industry Air Filtration and Ventilation Consultant, Tony Carvell, will be speaking at Food Safety Europe 2020 in London on 12th February. The BRCGS event, which takes place at County Hall, is a firm favourite with HVDS, as it brings together food industry professionals to discuss various aspects of food safety. It is an opportunity to share knowledge and learn from industry experts. Tony’s talk is about why it is important to take a holistic view of Indoor Air Quality. To book your place at Food Safety Europe 2020 or to find out more, click here.
We will also be exhibiting at Foodex 2020 at the NEC, Birmingham, from 30th March to 1st April. This will be the fourth time we have taken part in this show, and this year’s stand is the biggest and best for HVDS yet, showcasing all areas of our business including air filtration, fabric ducting, ductwork cleaning and dust, fume, mist, spray and oil extraction. Come along and see us on stand J201 in Hall 20.
After the success of our eFUSION™ app in 2019, which gives you 24/7 access to your air handling and air hygiene reports, we are proud to announce the MAXAIR™ app for our customers benefiting from our dust control service. The app will keep all your reports in place for easy access and audit purposes. More information to follow.
New for 2020 is our risk assessment template. In checklist format, this template guides you through everything you need to consider in order to comply with BRCGS Food safety Issue 8. It also highlights the level of risk where no action is taken. If you would like a copy of our risk assessment template, or would be interested in a full risk assessment by our trained engineers, please get in touch.
At HVDS, we recognise the value to our customers of providing useful information to help them maintain good Indoor Air Quality. For this reason, we are putting together a suite of resources that can be downloaded from our website for free. These include, for example, data sheets for each of our products, our HACCP Plan Template, our service brochures and checklists, such as this one about how to prolong the life and get the most out of your fabric ducting.
In 2020, we will continue to build on these resources. If there is anything you would find particularly useful, please drop us a line to let us know and we will do our best to provide it.
We will continue to listen to our customers to ensure we are giving them what they need and want. To help us with this, at the end on 2019, we conducted our Annual Survey. This highlighted the challenges our customers are facing and their priorities for the coming year. The results of this survey will be out later this month. Watch this space!
On behalf of the team at HVDS, we wish you all a happy and successful 2020!
This article looks at the combustible nature of powdered food substances and how to prevent explosions.
The Danger of Ingredient Dust and Powder
One of the most overlooked aspects of working with ingredients in a food production facility is that some ingredients can cause explosions. These substances include, for example, flour, sugar, dried milk, custard powder, instant coffee and soup powder. Common processes that can create explosive dust and food factory powder explosions are flour and provender milling, sugar grinding, spray drying of milk and storage of whole grains. Other processes include using finely sprayed oils, mixing with potable flammable solvents and certain sterilization techniques.
According to the Health and Safety Executive,
“If any combustible substance is mixed or suspended in air at the correct concentrations and contained in a vessel or building when ignition occurs, then a violent explosion can result. If it is uncontained then a fireball may occur.”
On 14th August 2015, a worker at Adams Foods in Leek, Staffordshire, suffered facial burns after a powder explosion. A spokesman for Adams Foods, which supplies ingredients to retailers, said,
“A member of staff working on the production line received minor injuries. Emergency services were called and the incident is now fully under control with all other production lines operating as normal.”
Fortunately, the injured worker was discharged after being treated at the Royal Stoke University Hospital. However, another similar incident could result in far more serious, and even life-threatening injuries. For more information on this story, click here.
For a FREE dust extraction survey of your site, please click here.
What Causes Powder Explosions
Food factory powder explosions are caused by combustible powdered substances in the air, coming into contact with a source of heat.
The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) are concerned with preventing or limiting the instance and harmful effects of such explosions.
According to HSE,
“In DSEAR, an explosive atmosphere is defined as a mixture of dangerous substances with air, under atmospheric conditions, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads to the entire unburned mixture.”
Considerations When Working with Combustible Powders
In order to operate your process plant safely and to meet DSEAR requirements, you must take the appropriate precautions. These precautions relate to storage and handling, pneumatic conveying systems, chokes etc. To read the recommended precautions, please click here.
Another issue to consider is your ductwork, which can get clogged with extracted dust particles. As well as presenting a significant fire risk, a massive build-up of can dust can even cause ducting to rupture, as a manufacturer of morning foods found recently. Please see our case study for further details.
Download our brochure about HVDS’ dust control services here.
HVDS offers a full dust control solution as per HSG258 and according to COSHH and ATEX regulations.
According to the World Health Organisation (WHO),
“Dusts are solid particles, ranging in size from below 1 µm (micrometre) up to at least 100 µm, which may be or become airborne, depending on the origin, physical characteristics and ambient conditions.”
Dust can be created by manual processes, such as cutting, crushing and grinding and particles can be so small that they are invisible to the naked eye. Different types of dust also carry different risks to human health and can be classified into three types: L Class (Low Risk), M Class (Medium Risk) and H Class (High Risk). Each class has a maximum allowable concentration, which is essential for employers to understand.
L Class Dust (Low Risk)
L Class dust is of lower toxicity and includes simple house dust, soil, general construction dust/waste, soft woods and solid surface material. The workplace exposure limit/maximum allowable concentration (MAC) for L Class dust is >1 mg/m3. This means that you need a dust extractor that catches 99% of the dust. For L Class dust, there should be a Filter Leakage no greater than 1% of the collected dust.
M Class Dust (Medium Risk)
Dusts in the M classification include hard woods (e.g. oak and beech), board material/man-made woods (MDF), repair compound, filler and clear coats, cement, tile cement, brick, mortars (silica), concrete dust, quartziferous materials (e.g. sand) and paints, such as oil paints and latex. They present a medium degree of risk to human health and the workplace exposure limit/maximum allowable concentration (MAC) for M Class dust is ≥ 0.1 mg/m³. Thismeans you need a dust extractor that catches 99.9% of the dust. For M Class dust, there should be a Filter Leakage no greater than 0.1% of the collected dust.
H Class Dust (High Risk)
H Class is high toxicity dusts containing pathogenic or carcinogenic particles, as well as asbestos, mould spores, bitumen, mineral fibres and artificial mineral fibres, like glass wool. They present a high degree of risk to human health and the workplace exposure limit/maximum allowable concentration (MAC) for H Class dust is < 0.1 mg/m³. This means you need a dust extractor that catches 99.995% of the dust. For H Class dust, there should be a Filter Leakage no greater than 0.005% of the collected dust.
Another category of dust, as highlighted by Health & Safety Executive (HSE) is combustible dusts. A combustible substance, mixed with air and with the addition of a source of ignition will cause an explosion. Workplaces that typically produce potentially explosive atmospheres include those handling fine organic dusts, such as wood or flour dust and those where processes release flammable gases or vapours, such as vehicle paint spraying. The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) make employers responsible for eliminating or controlling the risks from explosive atmospheres in the workplace. According to HSE,
“In DSEAR, an explosive atmosphere is defined as a mixture of dangerous substances with air, under atmospheric conditions*, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads to the entire unburned mixture.”
*Atmospheric conditions are commonly referred to as ambient temperatures (–20°C to 40°C) and pressures (0.8 to 1.1 bar).
There are two European Directives for controlling explosive atmospheres: Directive 99/92/EC (also known as ‘ATEX 137’ or the ‘ATEX Workplace Directive’) and Directive 94/9/EC (also known as ‘ATEX 95’ or ‘the ATEX Equipment Directive’).
Dust Control Considerations
It is important to use the right dust extraction equipment. In fact, HSE are giving out substantial fines where the wrong/no dust extraction equipment is being used.
When choosing dust extraction equipment the following should be taken into account:
- Type of dust you need to control (L, M or H Class, explosive dust)*
- Volume of dust to be extracted to match the extraction rate
- Storage capacity of the extractor
- Disposal of dust – with secure disposal required for H Class waste
* most L and M Class dust extractors will have similar suction rates and filtration levels
Different types of dust present different risks. At HVDS, we help you choose the right dust control solution for your particular workplace. For more information contact us here. To find out more about our dust, fume, mist, spray and oil extraction service, click here.