Leading the way in hazardous area static control

Each day there are fires and explosions caused by the ignition of flammable and combustible chemicals. One of the most common causes of the ignition is a spark caused by a sudden discharge of accumulated static electricity.

When two differing materials move against each other, electrons can be exchanged, leaving an excess of positive charge on one material and an equal negative charge on the other. This is the generation of static electricity. During the transfer or processing of a material, significant amounts of static charge can accumulate very quickly, leading to the rapid increase of voltage on the object (e.g. road tanker).

Voltages can rapidly exceed the break-down voltage of the surrounding atmosphere and create the risk of a sudden discharge to a nearby conductor in the form of a spark.
The amount of energy released by this sudden discharge can easily exceed the Minimum Ignition Energy (MIE) of the potentially flammable atmosphere and thereby lead to a fire or explosion.

The reason that controlling static electricity is so important for hydrogen safety is that the MIE is only a fraction of that of other fuels. This is highlighted in the following table taken from the ISO Technical Report ISO / TR 15916 ‘Basic considerations for the safety of hydrogen systems’.

The very small amount of energy required to ignite hydrogen means that it is classified within Gas Group IIC (Gas Group B in the US). Newson Gale’s Earth-Rite® II RTR is dedicated to grounding road tankers and large vehicles. It is certified to be installed and used in IIC environments, unlike many alternative systems.

Due to the harsh industrial environments in which grounding equipment typically operates, and because most grounding applications require many repeated connections and disconnections to process equipment, the robustness and reliability of the grounding solution is the primary concern with respect to intended performance. For that reason, best practice guidance such as IEC TS 60079-32-1 and NFPA 77 recommend resistance levels of 10 ohms or less between the object requiring static grounding and the verified
grounding point. The reason for this is that resistances higher than 10 ohms in the circuit between the object and the verified grounding point could indicate potential compromise of the grounding circuit, like a poor initial connection to the equipment via the grounding clamp, or loose / corroding connections that could otherwise prevent the passage of static charges to ground.

The most practical way to verify a resistance level of 10 ohms or less between the object to be grounded and the verified grounding point during the process is to use a monitored grounding system. A grounding system that continually monitors to a 10 ohm or less permissive threshold provides continuous indication of a connection that adheres to international standards and best practice recommendations.

The Newson Gale Earth-Rite® II RTR and MGV grounding systems verify that the true ground resistance is less than approximately 1000 ohms.

“Grounding devices should be clearly visible or be essential to the correct functioning of the fuelling station, so that any shortcomings are quickly detected.”

If all of the parameter checks confirm permitted levels, the Newson Gale Earth-Rite® II grounding system will give clear visual indication of the ‘GO’ condition from three high-intensity flashing green LEDs. If any of the checks fails to confirm a permitted level, a solid red LED indicates the ‘NO-GO’ condition.