The ultimate guide to hazardous process environments

Imagine a hose surface that's so hot that a moment's touch causes burns in seconds. A dry powder that produces tiny sparks as it's sucked from a silo to a production line. A concentrated acid that slowly corrodes the hose's inner wall from the inside.  

Although these scenarios play out very differently in everyday life, they all point to the same fundamental principle: the danger arises the moment the equipment is not suited to the operating conditions. 

In food, pharmaceutical and chemical production, you’ll find media, temperatures and atmospheres that can harm staff, process equipment and the end product. Some hazards are immediately apparent, whilst others build up over time. 

We provide you with an overview of the three most hazardous process environments and equip you to select the best components for them: extreme temperatures, explosive atmospheres and aggressive chemical media. 

A hazardous process environment is a production environment where the medium, temperature or atmosphere poses a risk. A risk to the people working nearby, to the equipment that needs to withstand the conditions, and to the product that must meet the requirements. It could be the steam system that makes the hoses scorching hot, the silo that fills the air with combustible dust, or the chemical line containing concentrated acid. 

These hazards rarely occur in isolation. In the chemical industry, you often encounter high temperatures and corrosive media on the same production line, whilst in food production, dust and static electricity frequently go hand in hand. Overall, there are three main types of hazard: 

• Extreme temperatures – hot surfaces and high temperatures 
• Explosive atmospheres – flammable dust, gas or vapour that can ignite 
• Corrosive chemical media – acids, alkalis and solvents that degrade materials 

When was the last time you realised just how hot a hose can actually get? 

In CIP and SIP processes, on steam systems, in oil refineries and petrochemical plants, the surface temperature can easily reach several hundred degrees. A single accident is enough to cause employees serious burns. The heat also wears down the hose itself. High medium temperatures cause the material to deteriorate from the inside, shortening its service life and increasing the risk of leaks if the hose is not designed for the task.  

To protect staff, a heat-resistant cover helps by insulating the heat from the medium and making the hose safe to touch. The cover can be fitted directly over an existing hose and sealed tightly without dismantling the line, or installed together with the hose from day one. With the hose cover, you thus create greater peace of mind for staff on the production floor. To address the other risk, it is a matter of choosing a hose material that can withstand the high temperature – not just now, but cycle after cycle. We’ll look at this later in the article. 

Some of the most dangerous environments are those where the danger is invisible. When dry powders, granules or flammable liquids move through a system, static electricity builds up along the way. And if a spark is generated in an atmosphere of combustible dust or vapour, the result can be an explosion. That is why antistatic hoses for conveying powders and granules are a key component in such environments. With proper earthing, the charge is safely dissipated before it has a chance to turn into a spark.  

Antistatic hoses are available in many variants, as media and operating conditions vary. Heavy powders such as grain and malt require a hard-wearing granule hose with a robust inner wear layer, such as our popular Air Food Antistatic. For finer, sterile or alcohol-containing media, a platinum-cured silicone hose such as our Pureway-SD Antistatic Platinum may be the obvious choice. It's important to remember that the material is only effective when it is suited to both the medium and the conditions to which the hose is exposed during use. 

If you work in areas where explosive atmospheres may occur, it's important to be familiar with the ATEX regulations.  

According to the ATEX directives, equipment must be approved for the specific zone in which it is used, taking into account how often and for how long the atmosphere may be present. It's worth remembering here that the zones are divided into two categories: one for gas, vapour and mist (zones 0, 1 and 2) and one for combustible dust (zones 20, 21 and 22).  

Many people primarily associate explosion hazards with gas or vapour, but in dairy production lines it's often combustible dust from sugar, flour or milk powder that poses a threat. And to prevent this, the hose's construction is a key factor. To be classified as antistatic, it must maintain its volume resistivity below a specified limit, typically R < 10⁸ Ω, but this figure is only effective if the hose is grounded via the couplings.  

The third hazard is the medium itself. Concentrated acids, bases and solvents can degrade a hose from the inside, long before any visible signs appear. The result is material fatigue, leakage and, in the worst case, a production stoppage. 

That is why the choice of material is one of the most important decisions. A standard material such as NBR quickly reaches its limits when exposed to concentrated chemicals, so you will usually have to choose between three other types of material: PTFE and FEP for aggressive media, and silicone for high-temperature, clean environments. It's worth understanding the practical differences between FEP, PTFE and silicone before making your final choice. 

However, the material alone is rarely sufficient. If the hose is used in an environment with explosive atmospheres or static electricity, it must also be antistatic and ATEX-approved. It's no coincidence, as chemicals, heat and the risk of explosion often go hand in hand in the process industry. 

This combination is a recurring feature in several hoses in our range. ChemForce ATEX, Prochim SPL/10-UPE and Dynamic Safe-Tech are all chemically resistant, antistatic and ATEX-approved. Which of them best suits your production line depends on the aggressive media and the conditions they encounter along the way. 

Regardless of the hazard that predominates in your environment, the choice of equipment follows the same principle. In practice, this means you should have four things transparent before making your choice: 

• The medium – what is flowing through the hose, and how corrosive is it? 
• Temperature – both during operation and during cleaning with CIP and/or SIP 
• Pressure and vacuum – does the hose also need to withstand negative pressure? 
• The zone – do you operate in an ATEX-classified area? 

Vacuum is a good example of how much detail matters – particularly if it occurs in a hazardous process environment. Two vacuum hoses that are antistatic and ATEX-approved may look the same, but behave very differently under negative pressure. The more precisely you can answer, the better we can get the solution right first time. And that's often where safety really comes into play: not in a single product, but in a hose that's been tailored precisely to the environment it's intended for. 

Are you unsure what your environment requires? Our specialists advise on precisely these kinds of choices every day and are happy to share their experience. Call us on +45 7020 0422 or send an email to inquiry@alfotech.eu.