March 17, 2017 10:58
The one BIG change to the latest ESD Standard you need to know about
Let’s face it: nobody likes ‘change’! We all like our little routines and feel comfortable with what we know.
BUT: without ‘change’, everything would stay the same; ultimately humanity would stagnate and die. So, let’s think of ‘change’ as an opportunity: to improve, to progress, to be better! That’s exactly the reason behind the latest major change to the ESD Standard: ensuring your ESD Programme is the best one yet and protects your ESD sensitive devices 110%.
You will have learnt by now that a fundamental principle of ESD control is to ground conductors including people at ESD protected workstations. Wrist straps are the first line of defence against ESD. A wrist strap is the most common personnel grounding device and is required for sitting operators.
A Flooring / Footwear system is an alternative for personnel grounding for standing or mobile workers. You will know that ESD footwear must be used in conjunction with an ESD floor and needs to be worn on both feet. But did you know that the latest ESD Standard now requires an Operator Walking Test and conformance to Operator Resistance Measurements?
The importance of the Walking Test
- The Walking Test is necessary to qualify the Footwear / Flooring personnel grounding system for certification to EN 61340-5-1.
- The Walking Test can provide records to prove that the Footwear / Flooring personnel grounding system used as a static control method is providing the performance expected.
- The Walking Test is also used when testing samples for qualification of a Footwear / Flooring personnel grounding system or on an existing installed floor when evaluating a change in footwear or flooring maintenance.
Performing the Walking Test
The Walking Test is completed with a device which measures the human body voltage generated while walking. There are different units on the market: some of them will display the results on the unit itself; others connect to a computer and use software to analyse the data. All units work in the same way though:
- You wear your ESD footwear.
- You hold a small probe (more like a rod) connected to the meter measuring your body voltage.
- While holding the probe, you walk across your ESD floor.
- You record the results and either calculate the average of the 5 highest peaks or let the software (supplied with some units) do the calculation for you.
Results of the Walking Test
The Walking Test simulates a real-world working environment with operators walking through an ESD Protected Area. The results will show the effectiveness of a Footwear / Flooring system to remove charges from the operator through the floor to ground. If the system is working properly, no more than 100 Volts will be generated on the body. For any Footwear / Flooring system, EN 61340-5-1 requires:
- the resistance from body to ground to be <109 ohms AND
- the body voltage to be < 100 Volts (average of 5 highest peaks).
Remember that the Walking Test must be performed on ALL ESD floors using ANY ESD footwear you may be using. So, if you have 2 EPAs with different flooring and use 2 different types of footwear (e.g. shoes, foot grounders), you need to perform a total of 4 tests to cover all possible options. Also, if you make any changes to your footwear or flooring (e.g. you change suppliers for your foot grounders or ESD floor cleaner), the Walking Test needs to be repeated to ensure compliance with the ESD Standard.
Vermason is a manufacturer of ESD protection products and was founded in Letchworth in 1979. Our mission is to maintain our position as the primary ESD solutions provider for the electronics industry in Europe. Vermason strives to manufacture quality ESD Control products with innovation, leadership and partnerships which deliver long-term commercial benefits.