News
Hand sanitiser spark risk warning
Industry groups like the Solvents Industry Association are concerned with reports of inappropriate packaging of solvents and an incident of a static discharge igniting vapours present on an operator’s hand after the application of hand sanitiser.
Mike O’Brien, managing director of Newson Gale, considers the approaches that can be taken in terms of managing the risk of solvents (including alcohols) being ignited by uncontrolled discharges of electrostatic sparks in a recently released guidance note.
The importance of grounding people
Managers of facilities where operators have exposure to potentially flammable or combustible atmospheres need to ensure the operators are grounded. This is because people isolated from a ground source (e.g. flooring capable of dissipating static charge to earth) can accumulate large electrical potentials beyond 20,000 volts without even realising it until they discharge a spark.
In addition, if operators are regularly applying hand sanitisers, either inside or outside a designated hazardous area, it is important to ensure that they do not have the potential to accumulate electrostatic charge on their bodies.
Ignition of vapours emanating from the hand can occur if the person approaches or touches a grounded object such as a door handle or stair railing, resulting in a static spark discharge with enough energy to ignite the vapour.
The most effective means of grounding personnel is safety footwear that meets the required static dissipative criteria and testing all footwear prior to entry into the facility is recommended. Easy to use footwear testers can be installed at designated entry points to hazardous areas in the facility.
Such testers utilise a simple plate on which an individual stands, with their safety shoes on, and presses a button with their index finger. If the resistance threshold of the shoes is below the required level, the test will indicate a positive output with a green LED indicator which
provides the operator with a “GOOD-TO-GO” message to enter the hazardous area.
If the shoes fail the test the indicator will stay red and the tester’s buzzer alarm will activate. At this point the operator should not enter the hazardous area and should report the failed shoe test.
Containers used in production and transportation
In relation to the use of containers, they should, ideally, be of an all metal construction so that when they are grounded, electrostatic charge cannot accumulate on the surface of the container. If the supply or use of fully metal IBCs is not possible, then the metal cages that contain the plastic container should be grounded. Splash filling should be avoided as this increases the rate of charge generation.
If electrostatic charge is permitted to accumulate the voltage of the IBC will rise very rapidly and result in this energy being discharged in the form of an electrostatic spark onto a grounded object like an operator. If the spark energy is sufficiently high, it will ignite the surrounding vapours with little effort.
It is not possible to cover every potential process involving the use of solvents. A more comprehensive summary can be viewed on the European Solvents Industry Group website.
https://www.esig.org/solvents-and-static-electricity/