Heaters Blog

Updates and news about Puravents range of industrial and commercial heaters, space heaters, LPHW heaters and radiant heaters.

Covid Safe Ventilation Of Buildings

Covid safe Ventilation of Buildings

As the ‘Lockdown’ is eased and staff return to workplaces there is an increased realisation of the need for adequate ventilation not only for worker and customer comfort, but also to minimise transmission of infectious diseases, including covid-19.

Covid safe ventilation of buildings is now understood to be vital to getting economic productivity growing again.

By ventilation, we mean the replacement of stale, and possible contaminated, air with fresh air from outside the building.  Although Covid-19 is the current issue, it is the same with any airborne viral contaminant. The air in the building is a potential conduit for infection from the infected to the uninfected. Continuous fresh air supply has the effect of diluting the viral concentration in the air. Buildings that are not ventilated enable the viral concentration to build over time.

Understanding that there is a need for Covid safe ventilation of buildings, the UK Health and Safety Executive (HSE) have issued Guidance on Ventilation and Air Conditioning during the Coronavirus outbreak which includes as its opening paragraphs:-

General ventilation. Employers must, by law, ensure an adequate supply of fresh air in the workplace and this has not changed.  Good ventilation can help reduce the risk of spreading coronavirus, so focus on improving general ventilation, preferably through fresh air or mechanical systems.  Where possible, consider ways to maintain and increase the supply of fresh air, for example, by opening windows and doors (unless fire doors). Also consider if you can improve the circulation of outside air and prevent pockets of stagnant air in occupied spaces. You can do this by using ceiling fans or desk fans for example, provided good ventilation is maintained.  The risk of transmission through the use of ceiling and desk fans is extremely low providing there is good ventilation in the area it is being used, preferably provided by fresh air.

Air conditioning.  The risk of air conditioning spreading coronavirus (COVID-19) in the workplace is extremely low as long as there is an adequate supply of fresh air and ventilation. You can continue using most types of air conditioning system as normal. But, if you use a centralised ventilation system that removes and circulates air to different rooms it is recommended that you turn off recirculation and use a fresh air supply. You do not need to adjust air conditioning systems that mix some of the extracted air with fresh air and return it to the room as this increases the fresh air ventilation rate. Also, you do not need to adjust systems in individual rooms or portable units as these operate on 100% recirculation. You should still however maintain a good supply of fresh air ventilation in the room.

The emphasis from HSE is clear. For Covid safe ventilation you need fresh air.

Covid Safe Ventilation – Long Term Solution or Short Term Fix?

Covid Safe Ventilation with a fan and flexible duct

A short term fix. Portable ventilator and duct. Fast, versatile and cost effective

This is the most topical of questions and it is exercising the owners and managers of work places and commercial spaces across the country and of course no one knows the answer because we don’t know how long the pandemic is going to remain a threat to our workplaces.

A short term fix to Covid safe ventilation is to use temporary ventilation. This can be as simple as using a combination of a portable ventilation fan and some flexible ducting. A permanent installed installation would require at least installed fan(s) and installed ducting.

But there are two problems, firstly to work out how much fresh air is necessary and secondly the loss of heat in winter.  In the summer the short term fix is easy – air may be introduced naturally via open door(s) and/or mechanically by using portable ventilation fan(s) either blowing fresh air in or pulling stale air out with the balancing flow coming via open windows and doors. However, as the summer draws to a close and the prospect of having to heat a large volume of fresh air looms large, attention is increasingly turning to permanently installed solutions complete with heating and/or heat recovery.

Covid Safe Ventilation – How Much Fresh Air?

In the UK, legislation exists setting appropriate standards for fresh air change rates. Building Regulations set out the minimum requirements for ventilation for new building construction. Approved document F (2010) expresses air change rates in a number of different ways:

      • air changes per hour.
      • litres per second (l/s).
      • l/s per m2 of internal floor area.
      • l/s per piece of equipment.
      • l/s per person.

The most commonly used expression of ventilation rate is air changes per hour and this terminology is widely used to guide ventilation rates for different types of application. The following table is generic and similar to others developed over the years before the current pandemic.

In the light of the Covid-19 pandemic of 2020 and the possibility of further waves of this and other Coronaviruses in the future, employers need to consider if their buildings offer the occupants Covid safe ventilation rates.

We have seen that many bodies representing different sectors are revising guidelines to specifically address their members concerns about Covid safe ventilation – dentists, healthcare, education, and building services to name but a few. The common thread to new Covid safe ventilation guidelines for the various sectors is that a far greater quantity of fresh air needs to be supplied.

In recent months we have discovered that even the basic ventilation rate of many buildings falls woefully short of even pre-covid guidelines (table above).  Building managers will need to work out if their buildings can offer satisfactory ventilation rates based on pre-covid standards, and if the current risk of covid-19 means that the rate should be increased.

Covid Safe Ventilation – Crunching the numbers

An example.  A room 10m x 10m x 4 m height has a volume of 400m3. If the room is ventilated at 1 air change an hour the resulting airflow is 400m3/h.  A higher ventilation rate of, say, 4 air changes per hour would mean an air flow of 1600m3/hr.  If the room is being ventilated at a rate of 100% fresh air, this means that there is 1600m3/hr of fresh air coming into the room.

However be aware that sometimes the term ‘air change rate’ is applied to ‘supply’ air.

Taking our example, if the room has 4 air changes of supply air and 25% is fresh, that means that 75% is recirculated through an air handling unit. So this means that the fresh air change rate is only 1 air change per hour. In terms of air flow it means that 400m3/hr of fresh is coming into the room and 1200m3/hr is being recirculated. The total supply to the room is 1600m3/hr. 4 air changes per hour supply, 1 air change per hour of fresh air, and 3 air changes per hour of recirculated air.

Covid Safe Ventilation –  Permanent Remedies

Across the country in buildings where there are mechanical ventilation systems, the air handling units are being adjusted to increase the ratio of

installed ducting can be part of a Covid Safe Ventilation system

Galvanised mild steel ducting

fresh air to recirculated air. In buildings where there is no mechanical ventilation employers must work out how to bring reliable large volumes of air into those building through open windows and doors using a variety of portable fans and flexible ducting.

duct fans are a vital part of a simple Covid Safe Ventilation system where there is no heat recovery

A typical duct fan from the KT range

But there is a problem as we move out of the the summer and into the colder seasons – if this fresh air is cold there will be either a huge impact on the comfort of employees/customers or on the heating bill of the owner/employer or both.  For some applications the additional heat will be within the capabilities of the existing system, however others will find that there is a heating gap to fill.

Any Covid Safe Ventilation system will need to introduce fresh air to the occupied space and this is where a huge selection of grilles and diffusers is useful.

Supply grilles

In cases where the Covid safe ventilation system is to be installed, in other words, a long term solution, a heat recovery ventilation system is well worth looking into. These typically have the exhaust air leaving the building through the same ‘box’ as the fresh air coming into the building. Inside the ‘box’ there is a heat exchanger that can reclaim 70% to 85% of the heat energy from the exhaust air and use it to preheat the fresh air coming into the building. As well as saving energy in winter they can also help cool the building in summer if you have air conditioning.

The big benefit to heat recovery in these uncertain times is buildings can be made safer by having higher rates of fresh air supply without a vastly increasing the heating and cooling cost.

Covid Safe Ventilation – Heat Recovery Solutions

Heat recovery using rotary heat exchangers can transfer bioaerosols from exhaust to fresh air. Not great for Covid Safe Ventilation

Thermal wheel heat recovery

Covid Safe Ventilation with heat recovery requires a counter flow heat exchanger

Counter flow heat recovery

This basic ventilation and heat exchange system comes in many forms and sizes from small commercial and domestic scale units right up to large industrial units. The smaller heat recovery units tend to use counter flow heat exchanger blocks, whilst larger heat recovery units tend to be fitted with rotating heat recovery wheels, also known as thermal wheels.


Mark ERV heat recovery

Our range starts with Mark ERV units.

Larger heat recovery ventilation is offered by Topvex air handling units.

These heat exchange mechanisms are built into machines of various configurations and sizes. Some are of a shallow profile and designed to be installed above ceilings to neatly hide the unit and ducting. Larger units such as the Topvex range are upright and would typically be floor mounted or perhaps hung form roof support structures.

Save VTX vertical has the ports in the top of the unit making it an ideal unit for smaller applications where it can be located in cellars or cupboards etc.

What these machines all share is some form of heat recovery, two fans (for the supply and exhaust flows), and some basic grade filters. The Topvex range offers further offers numerous options for heating, cooling, control and levels of filtration.

Topvex ceiling suspended air handling unit with heat recovery

We have over 250 options on our website – take the pain out of your search and contact us to discuss your specific needs.

Please contact us on 0845 6880112 or email info@puravent.co.uk with your project details.




Coronavirus – Service Update Letter

Dear Customers,

The team at Puravent very much hope that you are managing to keep clear of the dreaded Covid-19 and are coping as well as can be expected with the ‘new normal’.

Having been locked down with the rest of the country and on a rather restricted ‘operate from home’ operation, I am delighted that we are now back and operating from our office and normal service has been resumed.

Thank you for taking the time to visit our website and your interest in our products.

Stay safe.

Yours sincerely,




Bill Anderson


Wall Mounted Industrial Fan Heaters

Electric wall mounted industrial fan heaters don’t perhaps get the attention they deserve. Shame because they are a very easy and effective way of heating smaller working environments.

When most people think about wall mounted fan heaters, what comes to mind is a small domestic 1.5kw or 2kw unit with a pull string, whereas we like to think a bit bigger. In fact we don’t do domestic ones, only industrial wall mounted fan heaters where they can easily be large enough to deliver 30kw of heat.

Panther heaters operate with a remote controller and thermostat controlling up to 6 heaters
Heat/fan speed Contoller
TAP16 Thermostat

Advantages of wall mounted industrial fan heaters versus a portable fan heaters?

CAT heaters range covers up to 9kW

Whatever the size of wall mounted fan heaters their great advantage is that they are easily installed and once on the wall and connected up, they are out of the way. Although there are plenty of different models of portable heaters, and some of them excellent, there is the ever present power lead and the chore of moving it out of the way when you need the bit of floor that it is on, for something else. Whereas portable fan heaters tend to get moved around for best effect on work areas within in larger buildings, wall mounted fan heaters are better for whole room heating in smaller working environments. This means that in workshops, small industrial units, laboratories, shops, consulting rooms and the like, electic wall mounted fan heaters are ideal.

Wall mounted industrial fan heaters – single phase

A conventional 230 v single phase electricity supply is a little limited for the purposes of heating work environments. In broad terms 230v supply limits your choice to heaters that are not much bigger than 3kw. Whilst this may be ok for very small applications, once your heating requirements demand multiple 3kw heaters, you will very quickly run into limitations on the capacity of the power circuit that you might have been planning to plug the heaters into. When faced with this limitation many customers investigate the costs of installing a 3 phase supply.

Wall mounted industrial heaters – 3 phase

As with any other electic heater type the availability of 3 phase supply opens up the potential options hugely, compared to single phase. For most industrial environments where there are electrically driven machines 3 phase is not a problem, all the machinery will operate on 3 phase and the 3 phase circuits will be in place. The existence of 3 phase not only opens up the range of heaters available but also the range of heating capacity that is available and with up to 30kw generally being the upper limit on 3 phase wall mounted heater capacity.  With that size of heater available there is scope to heat really quite large industrial and commercial working environments using these heaters, but in reality when the application size is of this size running costs have much more impact and tend to outweigh the electic wall mounted heaters ease of installation and modest capital cost.

Industrial wall mounted industrial fan heaters for challenging environments.

Many working environments are challenging to heat because of dust, vibration, damp or corrosive atmospheres. The easy availability of wall mounted fan heaters specifically designed to be compatible with these type of environments make this type of heating an easy option and more attractive than more complex and expensive alternatives. 

Elektra industrial wall mounted fan heaters for extreme environments
Elektra wall mounted fan heaters for extreme environments

For these difficult applications we tend to look first at the Elektra range of heaters.  These heaters can be either wall mounted or free-standing – the bracket doubles as a stand when on the floor, and there are sub ranges suited to damp environments/ vibration/ dusty and fire risk environments and for producing elevated heat levels.  The Elektra heaters are well certified and versatile

The way the Elektra heater range works is as follows.

Application typeDamp and or
corrosive environments
 Marine  Dusty and/or
increased fire risk
Needing elevated heat
Outputs/supply3kw/ 230v
6kw/ 400v~3ph
9kw/ 230v~3ph
15kw/ 400v~3ph
3kw/ 230v
3kw/ 400v~3ph
3.6kw/ 440v~3ph
5kw/ 400v~3ph
6kw/ 440v~3ph
3kw/ 230v
6kw/ 400v~3ph
9kw/ 400v~3ph
6kw/ 400v~3ph+N
9kw/ 400v~3ph+N
Insulation classIP65IP44IP65IP44
Approved for use in combustible area
Useful featuresOuter casing in acid proof steel2 of the 3 phase models may be run from 60Hz supply. Vibration Resistant.Relatively low element temperature makes it ideal for dusty environmentsHigher temp. safety cutouts than standard enable much higher output temps.

Are you Wasting Heat and Energy?

Investing in destratification fans pays back instantly in terms of worker comfort also pretty quickly in terms of £££s as its puts an end to wasting heat and energy. Destratification fans can be retro-fitted to almost every workplace with immediate benefit.


Frico 9kW wall mounted fan heater

We recently quoted for a couple of Frico 9kW unit heaters to a client to heat his small manufacturing unit.

We also quoted for a thermostat to control the heaters and help to minimise his energy bills.


Room thermostat


Airius destratification Fan

To complete the offering we quoted for a small Destratification Fan to further minimise the bills by returning rising hot air from the ceiling of the factory to the working area (i.e. where the people are).

The client went ahead and bought the heaters and thermostat but did not proceed with the Destratification Fan.

A few weeks later we got a message to the effect that the heaters were working flat-out, the ceiling space was toasty (wasting heat and energy), but the workers were still cold! After some discussion the client decided to buy and install the Destratification Fan albeit with a little scepticism.

Today we got the following message and photographs…..

Hi Bill/Robert


Two heaters and a destratification fan in use in a small manufacturing unit

You will be happy to know that the Airius 15 destrat fan is working a treat !

Heating is actually switching off now.  Fingers crossed the bills reduce too.

Appreciate the help and advice. Attached photo which you can use if you want.

…and here is the photo they sent, with the two heaters wall mounted with isolator switches towards the right of the photo and the fan hanging from the ceiling joist near the centre.

We have hundreds of heating and ventilation options available on our website so if you require any assistance please do call us to discuss your requirements on 01729 824108. Alternatively email through your enquiry to info@puravent.co.uk or follow us on Facebook or Linked In

UV Air Purifiers

UV Air Purifiers and its Application

To achieve biologically and, or chemically clean air, UV air purifiers are the answer.  In this post we reproduce (with minor updates) our article that was originally published in MBS magazine in 2008. It is as relevent now as it was then. In  the meantime if you need help with engineering a system based on UV air purifiers then call us 01729 824108 or our UV products are here.

“In North America, UV air purifiers for preventing fouling on cooling coils and drip pans and for the treatment of odours and micro organisms in ducted air has been common place for 15 years or more. Not only is the technology a specified requirement for air handling units entering service within American public sector buildings, it has even been tested and found to be effective by the US National Homeland Security Research Centre, at defending building occupants against bio-terrorism. Now that the technology is detailed in the ASHRAE handbook, it warrants closer examination in Europe.

Technical Rudiments
Within the UV light spectrum, the wavelength 254nm is known to be particularly effective at killing or inactivating micro-organisms. It is utilised by ultraviolet genocidal irradiation (UVGI) systems, where the effect on micro-organisms, including bacteria, viruses and spores, is that it penetrates the organism’s cell wall and damages the DNA, preventing cell division reproduction; certain doom, given their short lifespan. Another useful UV wavelength is 187nm, which is sometimes known as UVV and is used for UV photo oxidation of airborne chemicals and odours. UVV produces ozone, oxygen singlets and hydroxyls (O3, O and OH), which although excellent for treating airborne odours and other chemicals, can leave harmful concentrations of residual ozone being supplied to occupied spaces. For this reason UVV is only used if followed downstream by and interlocked with, a UVGI system which acts as a catalyst reverting residual O3 safely back to O2. Within ducted systems, UV comes in two main guises.

UV Air Purifiers. In this case UVV and UVC lamps used in a combined system

Two UV air purifiers used in series, UVV and UVC combined for both biological and chemical challenges

For treatment of odours and chemicals UVV and UVGI lamps must be used in combination.

Coil Cleaning
Firstly UV lamps arranged to bathe the cooling coils and drain pan of an air handling unit in UVC light is used to prevent the build up of mould and slime. Left unchecked the cool, wet surfaces present an ideal breeding ground for biomass, blocking fins and reducing thermal efficiency, and creating a source of biological contamination easily picked up and vented to rooms. UV coil cleaners prevent this biomass with the economic benefit that the initial efficiency of the coils is maintained and the costs and down-time associated maintenance and coil cleaning are eliminated.”





Flood Damage – Top 10 building drying tips

Flood Damage – Top 10 building drying tips.

Your essential guide to drying rooms and buildings after a flood disaster.

Building drying in progress

Extreme weather events are increasingly leading to costly flood damage to domestic and commercial properties

The rain lashes down, drains block with fallen leaves and silt. The flood waters rise and search for new destinations. Houses, businesses, shops, offices, schools – the flood water does not discriminate between building types, only what ‘level’ they are at.  Although these days flooding can arise at any time of year it is still a particular problem in autumn. Buildings affected can be anything from a bit damp to massively damaged by flood water.  Here we provide our top tips for drying out buildings and rooms affected by flooding. These top tips are as useful for drying up after a burst pipe, or bath overflow as they are for a rainwater flood, and should help you get dry in quick time.

1.  If insured, discuss your claim and drying requirements with your insurer. They may hire a contractor to do the drying for you, in which case you can concentrate your attention on saving your contents and making sure that those you are responsible for are accommodated somewhere else. If it is a small drying job, perhaps one that is uninsured, or one that is not worth claiming for then the next 9 top tips are good to go, so long as you can establish that it is safe to do so by first consulting an electrician and perhaps a plumber.

2. Whats wet? No, it’s not a stupid question but the answer will affect how you dry the building and what equipment you use.

Say you have a traditional British type constructed building and the masonry walls and the suspended floor, complete with carpets is wet, then what you are looking at is potentially using a puddle pump (to pump out any remaining flood water from under your floor), a carpet dryer fan to blow air under the carpet, dehumidifier and a radiant heater.

puddle pump for Building drying

Puddle pump – Good for pumping out flood water from under suspended floors

Big building dryer, otherwise known as an industrial mobile dehumidifier for Building drying

Big building dryer, otherwise known as an industrial mobile dehumidifier

Mobile radiant heater ideal for warming walls and Building drying

Mobile radiant heater ideal for warming walls

Carpet blower for Building drying

carpet dryer designed for blowing air under a carpet so that the air gets a chance to dry the floor underneath and underside of the carpet

Alternatively – If you have a modern solid floor with tiles, timber or laminate flooring, then the chances are that it has been laid with an insulation layer which is saturated and needs to be dried before it can again be an effective insulating layer. For this you will need a restorative drying unit  (to suck water out from the insulation layer under the floor), a dehumidifier and a radiant heater.

Restorative dryer, designed to dry out insulation layers under floors and in other difficult places for Building drying.

Restorative dryer, designed to dry out insulation layers under floors and in other difficult places.

Big building dryer, otherwise known as an industrial mobile dehumidifier for Building drying

Big building dryer, otherwise known as an industrial mobile dehumidifier

Mobile radiant heater ideal for warming walls and Building drying

Mobile radiant heater ideal for warming walls

3. Use as big a dehumidifier as you can afford. Basically a little domestic plastic cased machine will not be up to it. You will need a big mobile dehumidifier – consider 30 ltr/day extraction rate as the bare minimum for drying a flood damaged small room. Bigger is better and quicker. More than one room to dry ? Then consider using extra dehumidifiers.

CR40 for Building drying

With only about 11 or 12 ltr/day removal rate @ 20 °C, it will take a long time, but is better than nothing


dehumidifier for Building drying

A bit bigger and a bit better

Big building dryer, otherwise known as an industrial mobile dehumidifier for Building drying

Bigger yet, even better and quicker


4. When using a dehumidifier make sure to minimise air ingress into the building. Close all doors and windows and trickle vents (if you have them). The idea here is that by keeping the building air sealed, that the air in the building can be made as dry as possible with the dehumidifier, without giving it the extra burden of drying extra air from outside.

5. Ensure the dehumidifier is positioned so that it can treat the air without any obstructions. Placement in the middle of the room is best. If you have a large room and a number of dehumidifiers working simultaneously, spread them evenly in the room and away from walls.

6. Use portable radiant heaters for heating up surfaces, such as plaster work. Warm walls will evaporate water far quicker than cold walls. Either use conventional portable radiant heaters or use radiant masonry drying panels.  Don’t put them too close to the wall otherwise you will get a hot spot, but place them a distance away so that a greater area is gently warmed.

Set back from a wall it will provide heat to a large area of wall to speed drying and Building drying

Set back from a wall it will provide heat to a large area of wall to speed drying

Masonry dryers are ideal for drying plaster and for drying out walls and Building drying after flooding

Masonry dryers are ideal for drying plaster and for drying out walls after flooding


7.  Add extra heat. Radiant heaters when used will also (in time) warm up air in the building, but if it is still cold in the room or building put in electric space heaters to raise the air temperature. Don’t use direct fired oil or gas heaters for this purpose as they will deplete the oxygen in the building. If you need more heating power, beyond what the mains supply to the building can safely provide via electric heaters, then use indirect fired oil or gas heating, with the heater located outside and warm air ducted in, ideally on a recirculation system so that heat is not wasted to the outside.   Ideally the building air temperature needs to be raised to at least 20°C. The warmer the air is the more moisture it can hold, the more water will evaporate from surfaces, and the more efficiently the dehumidifier(s) will work.

indirect oil fired heater can deliver about 29kw of heat for Building drying

Arcotherm EC32 indirect oil-fired heater can deliver about 29kw of heat to a building. This model can not be fitted with a recirculation duct

Kroll HM200 indirect gas fired heating plant for large heating and Building drying jobs

Kroll HM200 indirect gas-fired heating plant for large heating and drying jobs. This model is fitted with a recirculation duct


FF3 for Building drying

FireFlo FF3 portable fan heater, ideal for putting extra heat into a room that is being dried


8.  Work out what happens with the condensate collected by the dehumidifier. If it collects in a tank, remember to frequently empty the tank. If you do not do this the dehumidifier will stop to prevent it spilling the condensate on to the floor.   If it has a continuous drainage arrangement make sure that it can flow by gravity to a suitable drain.  If the dehumidifier has a condensate drain that is great, because it means that you can get the condensate to a drain more or less anywhere within reach of the hose that you attach to the dehumidifier and means you can leave the machine to work for long periods. If necessary slightly elevate the dehumidifier on blocks of some sort so that the gravity drain will operate successfully.

9. Consider putting air circulator fans into the building. If there is not enough air movement from the various machines in the building, the dehumidifiers, heaters, carpet dryers etc., you may discover that some areas are holding air pockets which are being left by the general air circulation. In this situation use fans to move the air in these areas.

10.  Use a moisture meter to track drying progress. With active drying there is a danger that walls and floors appear to be dry when they are still damp under the surface. 2 pin or 4 pin moisture meters can be purchased for as little as £10 and they tell you what is happening in the wall rather than what is happening on the surface.  If you don’t get this right, you might think your building is dry and as soon as you remove the dehumidifiers and drop the heat to normal levels, damp will reappear.  Also use feel to determine how the building is drying. Drying of walls will start at the top of the wall and dry towards the base. As you run your hand over what appears to be a dry wall, top to bottom you will probably notice the temperature of the wall cool, part way down. This will be roughly where the wall has dried down to.

These Top 10 Building Drying Tips are designed to give a brief overview of the challenge drying a building or perhaps a room. The Guidance and standards for drying flood damaged buildings provides a really comprehensive guide to the subject and has much more information.

For more information or want to hear from one of our specialists, visit our website for further details.

Gas Plaque Heaters

Gas Plaque Heater

For industrial zone heating it is difficult to better the quick heat up times and economy of gas plaque heaters

Gas Plaque Heaters: Application

Gas plaque heaters are perhaps the most effective and economical method of providing quick warming zoned radiant heating to large buildings. Gas as a heating fuel, particularly mains natural gas has long been seen as a cost-effective fuel, and when used in a radiant zone heating format provides for true efficiency.

Zone heating is ideally suited for large industrial building because typically one air space will have several areas with differing (if any) heating requirements. For example there will typically be areas put over to raw materials and finished  product storage which don’t  necessarily need heating, areas where there are sitting staff needing heat to one temperature and areas where there are other staff moving about doing more strenuous work which need heating but to a lesser extent.

With radiant heating you can discriminate between these areas, even leaving some areas within the same air space, unheated. Moreover the area heated can be narrowed by the choice of gas plaque heaters and the height at which the radiant gas plaque heaters are mounted. Generally the higher the plaque heater is mounted the greater the area heated beneath, and the greater the heating power required from that heater. Contrast the selective nature of zone heating with radiant heaters with the all or nothing method of space heating the air in the complete building. No wonder gas plaque heaters are so popular in our industrial buildings.

Puravent’s Range of Gas Plaque Heaters

At Puravent we supply the Infraglo Flamrad range of heaters, which have 6 sizes ranging in output from 3 kw to 27kw. Not that they all run on natural gas – for each size there is a variant which will burn propane for the applications where natural gas is not an option.

Control Fuel Heater Output
3kw 7kw 10.6kw 13kw 21kw 27kw
Automatic Propane 703A-P 707A-P 711A-P 713A-P 721A-P 727A-P
Natural Gas 703A-NG 707A-NG 711A-NG 713A-NG 721A-NG 727A-NG


The Flamrad Gas Plaque Heater Range

These automatic gas plaque heaters have spark ignition and flame monitoring. In the event of flame failure, lockout of the appliance will ensure complete safety; the unit can be reset by interrupting the mains supply. The heaters lend themselves to control by time clock, thermostats or energy management systems.



Gas Plaque Heater7
Gas Plaque Heater6

Infraglo gas plaque heaters features

Infraglo Flamrad gas plaque heaters features



As well as the single burner models in the Flamrad range there are also double head gas plaque heaters. These heaters typically find their application in areas of the building away from the side walls, and are hung to cast radiant heat on the staff work areas that are out of reach of wall mounted heaters.

Gas Plaque Heater4 Gas Plaque Heater3 Gas Plaque Heater2

Like any direct fired heating system used inside a building, it is essential that the minimum ventilation requirements are met in the building. When these units are installed by a Gas Safe registered fitter, they will ensure that there is sufficient fixed ventilation for heater and that the minimum fixed ‘free area’ of ventilation grills is at least met and preferably exceeded.

Heating Industrial Workplaces

The Inside Track On Heating Industrial Workplaces

The temperature of heated industrial workplaces has a bearing on some aspects of health and safety, but also on productivity, the integrity of the building and indeed, whats inside it. It is not law, but it is widely recognised that workers perform best between 16°C and 24°C, depending on what kind of work is being done. Higher physical activity levels, i.e. manual labour, is performed best at lower temperatures and incurs less risk of heat related stress. Conversely office work and fine, dexterous work will require a slightly higher temperature.

According to the Chartered Institute of Building Services Engineers, (CIBSE) different working environments require differing temperatures. For example:

  • Heavy work in factories: 13°C
  • Light work in factories: 16°C
  • Hospital wards and retail: 18°C
  • Offices and dining rooms: 20°C

In addition to the obvious consequences of not enough heating, occasionally there are instances of badly specified, designed or poorly controlled heating resulting in overheating, where issues can include low levels of employee concentration, dizziness, fainting, or even heat stroke. This oddity can arise where the fabric of an old building has been upgraded to modern standards but the old and consequently over sized heating system retained.  Apart from the social consequences, carbon footprint and energy costs will be far higher than required. Not only can this be attributed to the use of the wrong heaters, but also lack of proper heater control as well as poor ventilation and air circulation.

Types of Heating

Gas fired

Direct Gas Heaters

heating industrial workplaces gas fired heater

Arcotherm GP105M 108kw Direct Gas Fired Heater

Direct gas heaters are useful for heating workplaces with large open spaces, such as warehouses and industrial site environments. To use mobile gas direct fired heaters, sufficient ventilation of the room is essential to prevent a deficiency in ambient oxygen levels, and to prevent humidity levels getting too high. Direct fired gas heaters have been traditionally used to heat workshops, warehouses, construction sites and foundries, and for many years have been the automatic choice of the hire industry.


Indirect Gas Heaters

Mark GSX Gas Fired Heater

Mark GSX, ideal for heating industrial workplaces using gas

Often known as gas unit heaters, these indirect heaters are almost the standard installed heating solution in industrial buildings. They produce clean dry heat and combustion gases are expelled via a flue to outside. They are efficient for a number of reasons but one is that they are designed to use a balanced flue. This means that the combustion air is drawn from outside rather than warm indoor air. It means keeping the warm air inside and the outside air to the outside. Conversely if air was drawn from inside the building then the it would result in an outflow of air via the flue from building which would result in a lower pressure in the building meaning that outside air would use any pathway into the building (cracks, window seals, door seals etc) and drafts. Using indirect gas heaters for heating industrial workplaces is reasonably cost-effective, but the cost of equipment and installation is a bit higher than electrical heating

Fixed Gas Radiant Heating

Gas Plaque Heater

Gas Plaque Heater


With remarkably fast warm up times gas plaque heaters are really useful for heating industrial workplaces. They tend to find their application in industrial buildings where the heating requirement is more ‘occasional’ than ‘full time’. There are various small portable products up to about 36 kw which are fuelled from bottled gas, and also fixed plaque heaters which can run on natural gas. The nature of these heaters is that they create CO2 so as with direct fired heaters, there is a requirement to ensure that there is sufficient ventilation to ensure that there is no build up of CO2 and humid air.

Oil Fired Heaters

Indirect Oil Fired Heaters

vwigm_ec32-1 These are most commonly used in the marquee / event / temporary structure industry to provide clean, dry, thermostatically controlled heat inside the structure, with the heater standing safely outside. They are also widely used in construction, horticulture and agriculture and for general space heating.

heating industrial workplaces

Arcotherm EC32 indirect oil fired heater

The Arcotherm indirect heaters are a popular choice for marquee applications where it is important to control the temperature to a pleasant setting to ensure that guests are comfortable. Heaters such as halogen heaters, patio heaters, cabinet heaters, and table heaters are not suitable for the application as neither have internal fans, and in addition can pose a trip hazard due to trailing power cables. The Arcotherm heaters however, are placed outside and out-of-the-way, leaving a clean aesthetic feel inside whilst providing warm, clean, dry air into the space.

Electric Heaters

heating industrial workplaces

Elztrip EZ20831 800w 400V ceiling (3-10m) mounted radiant heater

Radiant Electric Heaters

Industrial radiant heaters are ideal for applications where rapid warm up times are required and open buildings require zone heating that would be impossible with space heating technologies. Smaller portable radiant heaters are available in both 230v and 110v, whilst for installed radiant heaters there is a choice of ceiling and wall mounted heaters. Electric radiant heaters are even available for mounting heights up to 20m – ideal for high bay loading areas and covered yards.  However, the application is most suited to just heating specific work areas within a larger, relatively cold building. Radiant electric heaters also provide a rapid warm up time which can make them an ideal choice for buildings that get occasional use e.g. commumity halls.


Frico Elztrip Heaters in a Hot Yoga Application

Electric radiant heaters find an ideal application in Hot Yoga studios. Radiant Heating for Hot Yoga places significant demands on a heating system because not only does the heating system need to be able to bring the temperature up to around 40°C. It also needs to be able to maintain that temperature within a relatively tight control band. The best heaters to meet the demands for temperature and of controllability are ceiling mounted electric radiant heaters. The Frico range includes a model called Elztrip which has the advantage of having a clean white finish, which suits a studio environment. Levels of controllability are enhanced with a control system where the power to the radiant heaters is rapidly pulsed on and off, and where the duration of the off and on parts of the cycle are altered to suit the temperature resulting in a much smoother temperature control especially when compared to a basic thermostat.

Electric Fan Heaters

Tiger fan heater - ideal for heating industrial workplaces

Tiger fan heater

Industrial electric fan heaters bring the advantage of readily portable, easy ‘plug and play’ to heating industrial workplaces. There is a huge range of types and capacities. Some smaller ones are 230v or 110v, whilst larger ones are 415v 3 phase. Some are built to be ductable, allowing warm air to be directed to where it is need, possibly a drying process or into a room.  Some are wall mountable and have variants that are designed for dusty environments or very wet or corrosive environments or for creating hot environments. But the overall, industrial electric fan heaters are all about cost effectiveness and versatility.

The Tiger range of electric fans heaters, for example, has ratings between 2 kW and 30 kW, each with on board thermostat control. The fans are ideal for use wherever temporary but effective heating is required, such as on building sites, in warehouses, workshops, shops, exhibition halls, assembly halls and garages. You can even attach them to a wall.



LPHW Heaters

heating industrial workplaces

Frico SWH02 12kw LPHW fan heater with intelligent control

Low pressure hot water (LPHW) is a flexible means of distributing heat to various zones or parts of a building. In a commercial or industrial setting, LPHW fan heaters or LPHW radiant panels are used and can be easily connected to the piped infrastructure. A piped LPHW system is a long-term investment – part of the building. The heat source (boiler, heat pump etc. ) and indeed the heat emitters (fan heaters, radiators, radiant panels etc) are easily changed and upgraded from time to time, when required.

LPHW Fan Heaters

Where heat is available in this form then the use of LPHW unit heaters fed on hot water is invariably the most cost-effective and indeed versatile method of space heating a room or building.  LPHW is ideal for all commercial and industrial applications: retail outlets; leisure centres; exhibition halls; warehouses; factories; garages; workshops; plant rooms.

LPHW Radiant Panel Heating

recessed LPHW radiant panels

Ceiling recessed LPHW radiant panels

Heating industrial workplaces with LPHW can also be delivered in the form of ceiling mounted LPHW radiant panels. They create a clean look and come in various sizes to suit a variety of commercial and industrial workplaces.  They can be fitted within a suspended ceiling grid or suspended from a solid ceiling. The effect is that the heater blends to be part of the ceiling and it is very clean and neat. No surprise that this variety of radiant panel heaters are popular in schools, municipal buildings, and commercial spaces.



suspended LPHW radiant panels

Suspended LPHW radiant panels

Suspended LPHW ceiling panels are seen when the ceiling is the roof line and particularly where the roof itself is a feature of the building, these radiant panels can add to the effect. Without the constraints of a ceiling grid they are available with a wider array of widths and again come in various lengths.  All ranges have a system of jointing that ensures that panels can be combined to form a seamless run. These type of heaters are normally used in larger rooms such as sports halls and assembly rooms, and often feature ball covers to prevent balls getting caught on the top of the heater. This type of heater is also becoming increasingly common in ‘clean’ manufacturing settings.



 Steam Heaters


123L-S-H steam 13.2kw fan heater

Steam, which is often viewed as a means of powering the industrial past, is in fact still a feature of some of the larger industrial buildings. Where there is a steam infrastructure there are two heating options – fan heaters and radiant panels.

Steam fan heaters

Thermolier fan heaters are an industrial heating stalwart and are widely used on steam applications. Efficient heat transfer from steam to air and strategic placement of the heaters gives exceptionally fast warm up and practical heat control in large spaces. Requiring little or no maintenance, these heaters are tough and efficient, and are typically hung from the roof structure of from wall mounting brackets. There are vertical airflow versions available which are suited for mounting in the mid area of large buildings away from walls, where they can provide destratification as well as heating.

steam radiant heater
steam radiant heater


Steam Radiant Panels

Steam radiant panels are a niche line but can be useful in providing heat in zoned areas where the expense of putting electrical ATEX certified equipment is prohibitive. Depending on the heat requirement and steam pressure available in the pipework, we can work out the most cost-effective sizes and array of steam radiant heaters to deliver that requirement. The suitability of stream radiant panels for ATEX zoned areas will depend on the temperature class requirements of the zone, and the surface temperature of the panel and indeed the steam pipe will depend on the steam pressure. It means that the heater itself is dumb but the amount of heat it produces and indeed the temperature of the heater is down to the clever control of pressure in the piped steam. Any control system for the heaters whether it be based in zone or out of it, must have fail safe features to ensure that a maximum pressure in the steam pipe is not breached, so that the pipework and heaters do not stray beyond the required temperature class.

This is just a very short overview of just some of the general methods of heating industrial workspaces. There are a number of other methods and a vast range of products available from Puravent. If you need any help whatsoever to find your industrial heating system, let us know.

Discussion of Unit Heater Types

There are a wide range of Unit Heater Types on the market today. While many are versatile enough to be used in a wide variety of ways, others are designed for niche applications.

Whereas radiant heaters, operating at a very high surface temperature are suited to ‘spot-heating’ applications (of say, a particular workbench) they are not generally a good selection for space heating. In contrast to a radiant heater, Unit Heaters use a fan to produce a high-volume flow of air which distributes the heat generated evenly and efficiently around the environment in which it is installed. Any heater will have limitations as to how widely the heat can be distributed and for larger spaces multiple Unit Heaters may be required.

Although the heat is distributed in almost all cases by an integrated fan, the heat may be generated in a variety of ways. Selection is often driven by the most readily available and economical fuel for the user.

  • Unit Heater Types – Circulating Hot Water Systems

    Unit Heater Types - Hot Water Fed, Wall Mounted

    Wall-mounted Unit heater with hot water feed

    Unit Heater Types - Hot Water Fed, Ceiling Mounted

    Ceiling mounted Unit Heater with hot water feed

    Hot water is generated by a central boiler and is then circulated to one or more low pressure hot water (LPHW) unit heaters. These LPHW unit heaters are used in many applications, such as for heating shop entrances, warehouses, industrial premises, workshops and sports halls. The fans have a low sound level and offer reliable operation. Many have optional ancillary control equipment including electronic thermostat that starts/stops the fan and opens/shuts off the water flow. If heating is not required the fan may continue to run to provide ventilation if required. Multiple unit heaters can be controlled with a single external room sensor and set point adjuster. Some LPHW unit heaters are equipped with drip pans and drains and they can be used for cooling as well as heating.

  • Unit Heater Types – Steam Fed Heaters

    Unit Heater Types - Steam Fed Heater

    Steam Fed Unit Heater

    Some boilers produce hot water but others produce steam. Steam unit heaters are in many ways similar to LPHW unit heaters, however although they have a coil and a fan to blow the air through the coil, the coil itself is of a far heavier construction. The operating principle of a steam unit heater is slightly different to a LPHW heater in that the coil is engineered to make the fluid not only transfer its heat to the air but also to change state. The steam condensing in the coil liberates more heat than just cooling the steam but maintaining its steam state.  The output of steam unit heaters is greater with larger pressure in the steam pipe and the Thermolier steam unit heaters that we supply are ideal for connection to piped steam supplies with up to 10 bar.


  • Unit Heater Types – Standard Electric Heaters

    Unit Heater Types - Standard Electric Heater

    Wall mounted standard electric Unit Heaters

    These basic units range from 3kw upwards and are targeted at the medium sized industrial premises. Models are available for both single phase ands three phase applications. The hot air ‘throw ranges from 9 – 16 metres. To comply with Ecodesign Regulation (EU) 2015/1188 these units must be installed with an external thermostat (such as TAP16R accessory). TAP16R has adaptive start, week program and open window detection.


  • Unit Heater Types – Electric Heaters for Specialised Applications

    Unit Heater Types - Specialised Electric Heater

    Wall mounted specialised electric Unit Heaters.

    Selection will depend on the environment within which the heater is to be applied. The model shown is available in 4 versions. Elektra C is intended for corrosive and damp environments, for example, car-wash halls and sewage works with an outer casing of acid-proof sheet steel, rated IP65.  Elektra F has a low element temperature and is approved for use in combustible areas, for example, joinery workshops and agricultural buildings rated IP65. Elektra V is designed to withstand vibrations on ships and offshore platforms and is approved by Det Norske Veritas. Available for single and 3 phase systems, 50 or 60Hz and rated IP44. Elektra H is designed for rooms with high temperatures, up to 70 °C and is rated IP44.

  • Unit Heater Types – ATEX Rated Heaters

    Unit Heater Types - ATEX rated

    Heater with ATEX rated fan

    These heaters can be installed where potentially explosive gases may be present. They are suitable for Zone 1 and Zone 2 hazardous areas and for gas groups 11A and 11B. They must be mounted horizontally and operated where the ambient temperature does not exceed 40 C. The heaters are stamped T3 and can be used in areas designated T1, T2, or T3. These heaters are widely used in installations such as oil refineries, waste water treatment plants and paint storage areas. ATEX certified with robust 2mm thick epoxy coated steel cabinet, adjustable air direction louvres, over temperature protection, vacuum charged fluid-to-air heat exchanger  and built-in contactor.


  • Unit Heater Types – Oil, Diesel, LPG and Propane Fired Heaters

    Unit Heater Types - Marquee Heater

    Marquee packages can be Diesel, Oil, or Gas powered.

    Unit Heater Types - Duct Adaptor


    These are available in both fixed and mobile designs. For fixed systems it is likely that a large external fuel storage facility would be provided to facilitate economical bulk fuel deliveries. Mobile systems often include a small built-in fuel cell. Mobile systems are partticularly applicable to construction sites where permanent electrical connections are yet to be completed or for ‘Marquee’ events such as temporary concert venues, festival arenas, large weddings and other similar applications. A single heater may be ducted to multiple areas using a variety of duct-adaptors.

    Unit Heater Types - Oil Fired HeaterIndirect Oil Fired Heaters have become increasingly popular in recent years; designed for horizontal or vertical suspension, the units are used extensively in horticultural and agricultural applications, and are often used in conjunction with suspended, perforated ducting, for maximum heat penetration. These units can also be floor mounted, using an optional trolley kit is available to facilitate movement between sites. The pictured unit has an output of 81kW (280,000 BTUs / Hr), with an airflow of 7,100 m³ / Hr.


  •  Unit Heater types – Solid Fuel Heaters

Unit Heater Types - Solid Fuel Heater

Solid fuel Unit Heater

Ideal for industrial situations which produce large amounts of combustible waste. The heater pictured is designed to burn waste wood or logs to produce industrial quantities of heat delivered onto an air flow via its integral heat exchanger. The result is a space heater that looks a bit like a cross between a large wood stove and a conventional ‘bullet’ style space heater. Once installed will provide years of heat from waste wood for the cost of powering the fan.The tube heat exchanger in the top of the heater ensures that once lit, heat can be delivered quickly and easily on the air flow through the tubes. Fitted with a centrifugal fan it is suitable for connection of ductwork, to distribute warmed air to specific locations or even through to adjacent rooms.

  • Unit heater Types – Biomass Heaters.

Unit Heater Types - Biomass heater

Biomass Unit Heater

These are totally self-contained systems which are ideal for space heating industrial type environments. They run on biomass pellets and the pictured range has nominal heat outputs ranging from 43 to 300 kW. Each system has 5 principal parts; The burner housing and combustion chamber; An automatic pellet burner; Control panel and burner programmer; Pellet screw conveyor; Pellet container tank. The combustion chamber with piped exchanger is designed to achieve performances higher than 92%. The pellet container which may be attached to either side of the heater has a standard capacity is 190kg but larger capacity containers are available if required.

  • Unit Heater Types – Cabinet Heaters.

Unit Heater Types - Cabinet Heater

Cabinet Unit Heater

There is a huge range of cabinet heaters on the market with a variety of fuels and electrically driven fans. The pictured heater is in fact oil-fired and is supplied with an integral day-tank and power cord enabling plug-and-play operation in both fixed and temporary applications.


  • Unit Heater Types – Sizing Your System.

Selection of the most applicable size and quantity of Unit Heaters to gain optimum cost effectiveness in any particular situation is complex. There are a number of other variables that contribute to the overall calculation including:-

  • Ambient temperature outside

    Unit Heater Types - Destratification fan

    Destratification Fans will add to Unit Heater efficiency in high ceilinged buildings

  • Materials of construction and how well insulated the building is
  • The efficiency of the heating system
  • The control accuracy of the heating system
  • Fuel preference
  • The height of the space to be heated will determine whether destratification fan(s) would add to overall efficiency

Help and advice

If you would like to find out more or to get advice on reaching an ideal air circulation system for your application then email us at puravent@gmail.com or call us on +44 (0)1729 824108




HVLS Destratification Fans – A Guide

High Volume Low Speed destratification fans (better known as HVLS destratification fans) are able to provide great improvements in working environments, customer environments and  livestock housings, and better operating conditions for many types of machinery. Due to their whisper-quiet operation (<60dBa) the Evel HVLS destratification fans are applicable across a wide range of environments including for example – restaurants, hotel lobbies, large open plan office places, atriums, conferance centres, warehouses, manufacturing environments and livestock buildings.

What is ‘stratification’ of air?

Evel HVLS destratification fans

HVLS Destratification Fans ranging from 2.5m to 7m diameter are available

Stratification of air is due to the fact that hot air rises, leading to the temperature at ceiling level being higher than at ground level. It is generally accepted that in rooms with stratified air, the temperature differential is typically 2-3°C per 5m height but can be as much as 1°C/m height in some circumstances.  In the worst case, this means that in a 10m high room the difference between temperature at floor level and ceiling level would be 10°C. To achieve a comfortable working environment of say 18°C therefore entails heating the ceiling to 28°C in this circumstance and the higher the ceiling the greater the potential temperature differential, and the greater the likely savings from implementing effective thermal destratification fans.

How do HVLS destratification fans work?

HVLS destratification fans take in the warmer ceiling air and transport it to the floor in a slow-moving column to create a better working environment and greatly reduce total energy consumption. In winter the most significant benefit is a considerable reduction in the cost of heating to create the optimum working/storage environment. During summer months HVLS destratification fans provide low-cost ventilation, reducing or eliminating the need for air conditioning.

When are HVLS destratification fans used?

Evel HVLS Farming 1

HVLS Destratification Fan in use in a livestock application

These fans come into their own in larger applications where there is an economic advantage to using HVLS fans rather than typically up to 7 smaller conventional destratification fans. The increased cost per fan of HVLS fans will be offset by lower installation costs (particularly power and control cabling), lower ongoing operating costs (due to far more efficient motors and responsive control systems) and lower future maintenance costs (due to lower speed and automated, variable speed operation).

Where are HVLS destratification fans used?

In retail or manufacturing situations it is necessary to maintain a comfortable environment to maximise customer enjoyment and / or employee productivity. In high-tech environments a stable controlled environment is required for efficient operation of electronic equipment.

In warehousing it is often necessary to maintain certain air quality standards including temperature and humidity in order to maintain the quality of the stored materials. Similar requirements apply to indoor sports arenas. HVLS destratification fans are ideal for such applications as they are able to respond rapidly to changing environmental conditions.

Enclosed or semi enclosed livestock buildings such as poultry sheds, livestock wintering buildings and cow milking parlours will enjoy the benefits of energy savings and enhanced productivity and improved animal welfare when HVLS destratification fans are put in place.

‘Evel’ range of HVLS destratification fans

All Evel HVLS destratification fans incorporate brushless motor technology with integrated inverter to give optimum efficiency and also allowing remote control and/or monitoring of more complex environments. Fans may be controlled remotely as individual units or may be grouped together as a system and controlled by a central controller.

  • The ‘WD’ range – This range is particularly though not exclusively applicable to the Hotel / Restaurant / Small Commercial markets. These have  5 ‘Selig’ profile fan blades with a diameters of  2.5 – 4 metres rotating at between 160 and 250rpm. These are suitable for ceiling heights up to 7 metres.
  • The ‘WZ’ range – This range is aimed at the Industrial / Large Commercial / Farming markets. These have  5 ‘Naca’ profile fan blades with a diameters of 2.5 – 7 metres rotating at between 38 and 250rpm. These are suitable for ceiling heights up to 12 metres.

Sizing your system

Selection of the most applicable size and the correct quantity of fans to gain maximum cost effectiveness in any particular situation is complex, because there are a number of other variables that conribute to the overall calculation.These include,

  • Ambient temperature outside
  • Materials of construction and how well insulated the building is
  • The efficiency of the heating system
  • The control accuracy of the heating system
  • The actual temperature differential pre destratification
  • The effectiveness of the destratification fans
  • The running costs of the destratification fans
  • The pricing structure of the running cost to your heating system

Help and advice

If you would like to find out more or to get advice on reaching an ideal air circulation system for your application then email us at puravent@gmail.com or call us on +44 (0)1729 824108

LiveZilla Live Chat Software