Electrostatic build-up and its uncontrolled discharge can have serious consequences for people – we examined this in detail in a previous article. Now we intend to discover what actually makes PPE capable of discharging electrostatic build-up, how it can be checked and what products uvex offers in this areaet.
Electrostatic build-up and its uncontrolled discharge can have serious consequences for people – with both direct and indirect ramifications for the person affected. By way of example, we take the standards EN 1149 and EN 61340 and describe two scenarios which illustrate the difference between protective antistatic and ESD clothing.
There is often confusion between the terms ESD and antistatic, and not just when it comes to safety footwear. While one includes the other, to deduce the same is true in reverse is generally incorrect. Although both terms refer to contact resistance, there are fundamental differences between the two. Confused? Worry not. We are going to shed some light on the matter below. Read More
Some of the more visible effects of electrostatic build-up are familiar to us all: hair which stands on end when rubbed with a balloon or the occasional electric shock when closing car doors. However, there are some types of electrostatic build-up and discharge which could cause greater harm. For example, when electronic components are involved or where people are in industrial explosion hazard areas. A newly introduced test standard for safety gloves will now govern threshold values and test conditions.
Personal protective equipment (PPE) is subject to a raft of regulations, rules and standards. For example, if a glove is designed to protect against mechanical risks, the criteria regulating the corresponding certification are contained in the industrial standard EN 388:2003. Where chemical hazards are concerned, standard EN 374:2003 applies. In the past, there has been no binding standard to govern issues such as electrostatic build-up and/or fire and explosion hazards. Technical regulation for operational safety TRBS 2153 may well prescribe that the contact resistance of a glove must be less than 100 megaohms (108 Ω) for zones 0, 1, 20 and 21 of explosion hazard areas, but it does not contain any description in relation to test methods and criteria. However, standard EN 16350:2014, which deals with electrostatic characteristics of protective gloves, will come into force on 1 July 2015 – better late than never!
What does the standard cover?
EN 16350:2014 prescribes the following test conditions and minimum requirements for the electrostatic properties of protective gloves:
- The contact resistance of a glove must be less than 100 megaohms (Rv < 1.0 x 108 Ω)
- DIN EN 1149-2:1997 regulates contact resistance
- The atmosphere during testing for contact resistance must constitute an ambient temperature of 23°C (± 1°C) and have relative humidity of 25% (± 5%)
- Five tests will be conducted and each measurement must be within the threshold values
What is the state of play regarding ESD requirements?
The fact is that there is currently no standard for electrostatic discharge (ESD) and therefore also no clear, valid ESD labelling for protective gloves as is the case for protective clothing and safety footwear, for example. In this regard, the standard DIN EN 61340-5-1 applies, but it is not valid for protective gloves – even if the odd ESD symbol may be found on gloves in retail stores. However, gloves that have been tested and certified in accordance with the new electrostatic standard can now be used without qualms in areas which require ESD product protection.
What exactly are the differences between ESD standards DIN EN 16350, DIN EN 1149-1 and DIN EN 61340-5-1?
|Protective gloves||Protective clothing||ESD protective equipment|
|Standard:||EN 16350||EN 1149-1||DIN EN 61340-5-1|
|Name:||Safety gloves – electrostatic properties||Safety clothing – electrostatic properties part 1: Test method for measurement of surface resistivity||Electrostatics 5-1: Protection of electronic devices from electrostatic phenomena|
|Validity:||Industrial health and safety||Industrial health and safety||Product protection|
|Feature measured:||Contact resistance||Surface resistance||Depends on what is being tested (e.g. contact resistance for shoes, surface resistance for clothing)|
|Threshold value:||R < 1.0 x 108 Ω||R < 5.0 x 1010 Ω||Various requirements:e.g. footwear:7.5 x 105 Ω < R < 3.5 x 107 Ω
R < 1.0 x 109 Ω
|Test atmosphere:||Ambient temperature: 23°C (± 1°C); relative air humidity: 25% (± 5%)||Ambient temperature: 23°C (± 1°C); relative air humidity: 25% (± 5%)||Differs according to test (footwear, clothing, ground, work surface, etc.)|
|Measurements:||5 tests; each must be within the threshold value||5 tests; geometric mean must be within the threshold value||Differs according to test (footwear, clothing, ground, work surface, etc.)|
|Symbol/pictogram||none||Symbol with pictogram||Symbol with ESD pictogramWarning: does not apply to safety gloves!|
For which areas of application are certified safety gloves appropriate?
Gloves which have been tested in accordance with EN 16350:2014 can, among other areas of application, be used in explosion hazard zones such as refineries. Due to a high degree of conductivity, electrostatic build-up on wearers can be effectively avoided as long as the grounding chain, which consists of gloves, PPE, footwear and the ground, is uninterrupted.
Inadvertent electrostatic discharge can also have negative effects in the manufacturing and assembly of delicate products such as electronic components, which may suffer permanent damage or even be destroyed by such an event. Safety gloves tested in accordance with DIN EN 16350:2014 are also suitable for use in this area of application.
Does uvex also have certified safety gloves?
uvex responded to the new protection standard for electrostatic properties by developing its own uvex unipur carbon. These safety gloves are ideal for lightweight working environments and remain within all threshold values and fulfil the conditions prescribed by the standard, as well as offering exceptional haptic qualities and ensuring climate comfort. In the next few weeks, the uvex rubiflex ESD safety gloves combining electrostatic discharge capabilities and chemical protection will be added to the uvex product portfolio. This product is currently in the process of gaining certification. The uvex rubiflex ESD is perfectly suited for use in paint workshops, the colour and printing industries as well as in the oil and chemicals industries.
The uvex i-performance product system supports the natural movement of the human body, reducing pressure and stresses while also maximising comfort. Constant further development of our products is carried out on the basis of the latest physiological research and technology, thereby ensuring optimum performance with quantifiable product benefits.
The new uvex 9780 antistatic helmet falls under this category and offers an unparalleled level of protection. The merest spark can cause an explosion in environments which contain combustible gas, mist, vapours or dust clouds. It is therefore essential that employees are reliably protected against electrical discharge in many industrial workplaces. Specific danger areas where hazardous atmospheres mean that explosions are likely are divided into various zones.
The uvex 9780 antistatic is a helmet perfectly suited to being worn in explosive environments. It offers optimal protection for all danger groups and zones, in accordance with EN 60079 – 0 in connection with ATEX – guideline 94/9/EG.
What actually are explosive atmospheres and what do these zones mean?
As defined in the DSEAR, an explosive atmosphere is 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. When an atmosphere like this appears in dangerous quantities, meaning that certain safety measures must be implemented in order to maintain the protection of employees’ health and safety, then one can speak of a dangerous, explosive atmosphere.
These dangerous, explosive atmospheres are divided into fundamental zones (Zone 0, Zone 1, Zone 2, Zone 20, Zone 21, Zone 22 and Zone 23):- Zone 0: Danger zone in which an explosive atmosphere of gases, vapours or mist is present continuously or for long periods or frequently
- Zone 1: Danger zone in which an explosive atmosphere of gases, vapours or mist is likely to occur in normal operation.
- Zone 2: Danger zone in which an explosive atmosphere of gases, vapours or mist is not likely to occur in normal operation and if it occurs it will exist only for a short time
- Zone 20: Danger zone in which an explosive atmosphere of dust is continuously present or present for long periods
- Zone 21: Danger zone in which an explosive atmosphere of dust is likely to occur in normal operation
- Zone 22: Danger zone in which an explosive atmosphere of dust is not likely to occur in normal operation and if it occurs it will exist only for a short time
(Zone 0 is the most hazardous danger zone in which explosive atmospheres are present)
So what causes explosions?
Explosions are caused when the right air to gas ratio occurring at the same time as an ignition source becomes active. In addition, explosives can be caused by fluids and solids if these are finely dispersed, again in an atmosphere in which the air ration and ignition source are conducive.
Explosions with dangerous effects can occur when the following conditions are present at the same time and place:
- Flammable substance (concentration in air within the explosion arealimits and sufficiently finely dispersed)
- Oxygen in sufficiently high concentration
- Effective source of ignition with sufficient energy
If just one of these factors is missing, no explosion can occur.
The innovative material used to manufacture the uvex 9780 antistatic reduces ohmic resistance and deflects excess electrical discharge away safely and securely.
This is the first helmet on the market to provide employees with suitable protective headwear for working in closed containers and pipeline systems, as well as while equipping plants where flammable liquids can be found and explosive gases can build up (Zone O). Typical working environments include mining, the petrochemical industry and oil rigs, for example.
Please do not hesitate to contact us with any questions on the uvex i-Performance product system.
Please email firstname.lastname@example.org and we will be happy to help.