Explosion-proof air conditioners - about their price, how to purchase and safety in hazardous areas.

Do you want to purchase an explosion-proof air conditioning system? This article explains the most important issues you need to know when buying an explosion-proof ATEX air conditioner.  

Four important factors we will explain:

1. Which explosion-proof ATEX air conditioner is required?
2. What cooling capacity is required in a classified hazardous area? 
3. Safe installation, usage and maintenance of an explosion-proof air conditioner. 
4. What to know about the pricing process of explosion-proof air conditioning systems. 

Continue reading this page and buy the right climate control solution for your hazardous area. Ex-Machinery modifies air conditioners of all leading brands so they are certified and ready for safe use in hazardous areas - ATEX zone 2 (3G) and 22 (3D). 


 1.     Which explosion-proof air conditioner is required?

The  explosion protection document shows you the ATEX zone qualification that you will need to know for the specific ATEX zone you need climate control for. Zones 0, 1 and 2 are for gas explosion hazards. Zones 20, 21 and 22 are area classifications for dust explosion hazards. Please also mention what kind of gases or dusts are present, so we know what temperature class is required. Temperature classes vary from T1 to T6.

Figure 1: This is an overview of ATEX zones and ATEX equipment. Useful as a reference document. Read our full blog Practical overview of ATEX zones and ATEX equipment if you want to learn more about the used terms.  


2.     What cooling capacity is required in a classified hazardous area 

a. Factors 
The cooling capacity depends on the dimensions of the room. Additionally,  the outside temperature and heat produced by working machines have to be taken into account. Climate control in a crane cabin or porta cabin requires much less capacity than climate control in a MCC (motor control centre). MCC’s are larger and MCC panels produce a lot of heat.  
The outside temperature is an important factor in the Middle East, India and other countries around the equator. Cooling from an outside temperature of  30 degrees Celsius to a comfortable 20 degrees Celsius inside requires much less cooling capacity than from 46 degrees Celsius.

b. How to calculate the cooling capacity (BTU, kW, RT) for an explosion proof ATEX air conditioner?
This is how you calculate (in a simplified way) the cooling capacity, at an outside temperature of max. 35 degrees Celsius: 

  • Determine the dimension of the room (multiplying length, width and height in metres gives m3). Say you find 200m3.
  • Choose the right heat factor for your room: in practice, there are 3 factors to choose from:  

- Factor 30: limited room, well isolated, no flat or pitched roof, little heat generating equipment, and few workers present.  
- Factor 40: Not so well isolated and many workers and/or much gas and/or much heat-generating equipment. 
- Factor 50: A pinched or flat roof, many workers and much heat generating equipment. 

  • Multiply the volume of the room (200m3) x factor 50 = 200 x 50 = 10.000 Watt (10kW)
    Note.: if the equipment present has a capacity over 500 Watts, add this number to your answer. 

c. About BTU, kW and RT; and how to convert these numbers  
Cooling capacity of an air conditioner can be expressed in BTU (BTU/u, British thermal unit), Watt or RT. RT stands for ‘refrigeration ton’ and is used as a unit of power in some countries, (especially in North-America). And it comes from the rate of heat transfer that results in the melting of 1 short ton (907 kilo) of ice at 0 degrees Celsius in 24 hours. 

1 BTU/hr  = 0,29307107 Watts. 
BTU per hour to watts conversion 
Refrigeration tons to kilowatts conversion


3.       Safe installation, usage and maintenance of an explosion- proof air conditioner

The right installation is the most important part of safe use of an ATEX air conditioner. Only staff with knowledge of gas and dust explosion risks should perform the installation. Do not start installation or maintenance when an explosive atmosphere is present. 
A special work permit indicates that the location is safe. If an explosive atmosphere is not to be eliminated (i.e. due to a continuous production process), take the following measures: 

  • Use a LEL meter or LEL detector. This gas detector indicates the amount of combustible gases present. When a percentage of the lower explosive limit  (LEL) is exceeded, an alarm signal is activated. You can work safely below 10% LEL.   
  • Use an explosion-proof vacuum pump (when installing a split unit). 
  • Make sure that the connection box of the ATEX outdoor unit is grounded separately and use an explosion-proof maintenance switch.
  • Only use a damp cloth for cleaning the indoor unit. A dry cloth generates static electricity, which can cause sparks. 


4.     The price of an explosion-proof ATEX air conditioner

The price of a certified ATEX air conditioner is significantly higher, as compared with the price of a regular air conditioner. A good rule of thumb is a factor 3. And there is a reason for that. You can read here how to buy the most cost-efficient climate solution for your hazardous area.  

a. The ATEX zone 
Hazardous areas are classified in order of the likelihood that a gas or dust explosion actually will happen. The level of those risks are based on the frequency and duration of occurrence of an explosion atmosphere. The higher the risks, the stricter the technical criteria to reduce these risks.  
This explains higher prices for ATEX air conditioners in ATEX zones in general and higher prices in the most riskful zones - compared to the lesser risky zones. Besides meeting the technical demands, the manufacturer also faces higher claims in case of an explosion accident and has to go through more complicated procedures of certification for the high risk zones than for the lower risk ATEX zones. 

Tip: Lower the ATEX zone, if possible. Both technical and organisational measures lower the risks and therefore the zone. The right ventilation often makes a zone 1 into a zone 2. Placing (parts of) equipment outside the zone is always a simple and very cost-effective solution. 

E.g. you can place an access point outside the ATEX zone and connect it to an explosion-proof ATEX antenna inside the hazardous zone. Also, the use of alternative raw materials in the production process can change an ATEX zone into a non-hazardous area.  

For a split unit air conditioner, chances are that only one part must be explosion-proof, mostly the indoor unit. You then can use a regular outdoor unit, and only the indoor unit needs to be modified. This also saves a lot of money. 

b.  Capacity and type (window or split unit) ATEX air conditioning 
There are the same differences in prices for different models, and capacities for air conditioners for hazardous areas as for non-hazardous areas. There are some additional pricing differences caused by the fact that we talk about hazardous zones. 
Tip: If you, as a wholesaler or installer, keep stock or can buy at very competitive prices yourself…. you can provide Ex-Machinery with the air conditioning unit that needs to be modified. You then only pay for the modification and certification. ​

  • Indoor- & outdoor units
    Modifying an indoor unit is more simple than making an outdoor unit explosion-proof. That is why modifying an outdoor unit is more expensive than an indoor unit. Rarely are both the indoor and outdoor units installed in hazardous areas. Therefore, please specify which part needs to be modified. An ATEX indoor unit comes with a wall control or infra red remote control. The modification of a wall control is less complicated and therefore less expensive than the modification of a remote control into an explosion-proof version.  
  • Small rooms
    For smaller hazardous locations, like a crane cabin, porta cabin, analyzer housing or storage container for volatile substances, a window air conditioner is the most cost-efficient solution. Cooling capacities of up to 3.5 kW. Installation are simple and can be performed by regular maintenance staff. Making a window air conditioner suitable for hazardous areas is less complicated than a split unit, which also limits the price of an explosion-proof window air conditioner. In contrast, a split unit has two separate engines - one in the indoor and one in the outdoor unit, that both might be modified.
  • Installation process
    Installing a split unit air conditioner has to be performed by a specialist. This specialist solders and inserts cooling liquid under pressure. Although the split units are more complicated to install, they are more energy-efficient when used. The initial cost of installation may be more expensive in the short-term. However, the energy efficiency of this type of unit will ultimately result in significant long-term cost-savings - especially at higher capacities/more kW’s. Also, there is a wider range of models to choose from, like a cassette unit which fits in a standard ceiling tile, a ceiling suspended system, or a wall-mounted unit.

c. The ATEX certificate and taking responsibility for explosion safety 
The ATEX certificate is also a pricing factor. A certificate is both required and valuable. With the ATEX certificate, the manufacturer declares that he is responsible for the explosion safety of the air conditioner that he has modified to the ATEX standards. The ATEX manufacturer remains responsible, even after delivery by, for example, an importer or distributor.

The certificate refers to the underlying technical construction file (TCF) that has been prepared by or purchased by the ATEX specialist. Setting up a TCF takes a lot of time and requires a lot of knowledge of ATEX standards. Additional certificates are required when installing ATEX air conditioners in Russia, South Africa or the USA or Canada  - as ATEX are European guidelines.

d. Additional technical specifications of the ATEX air conditioner
Additional technical specifications also increase the price. An example is the application of offshore coating. Important on drilling platforms, industrial locations on the coast, or chemical sites where there is chemical corrosion. Ex-Machinery applies offshore coating at cost-price.
A redundant system, explosion-proof modified, also increases the price. A redundant system enables automatic switching on of a second air conditioner unit in case of malfunction. The redundant system increases safety and is a good measure to reduce the zone class. This results in cost savings, as regards mandatory safety measures. For example, when processing pure alcohol, a low ambient temperature guarantee is important. A low temperature prevents vaporization of the alcohol; vaporization creates an explosive atmosphere. 


Summary key factors regarding the purchase of an ATEX air conditioner: 

The zone layout can be found in the explosion safety document of the location.

The cooling capacity you need depends on the size of the room, the outside temperature and the heat emitted by equipment in the room. 

Only start installation or maintenance if there is no explosive atmosphere and work with LEL detection.

Finally, we explain why the price of an ATEX air conditioner is about 3x higher than an ordinary air conditioner. Also, additional technical requirements, such as offshore coating or a redundant system, affect the price.


About Ex-Machinery

Ex-Machinery has specialized in ATEX and explosion safety for over 14 years. Are you interested in explosion-proof equipment? Then please do follow our ATEX specialist Gido van Tienhoven on LinkedIn and he will keep you updated on ATEX and explosion safety. You can also send Gido your specific ATEX question at gt@ex-machinery.com. Please include your technical specifications. We are committed to working with you to help you find your ATEX solution. 

Please do read our blogs, which contain much interesting information on ATEX and explosion safety


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