FAQ - Emergency Stop Functions
Last update: 03 September 2023
Ahmet Erdinc
CMSE Trainer | CECE | B11 LMSS
See "About" section of Ahmet Erdinc's Linkedin profile for "Disclaimer" statement.
In this article, "emergency stop" is written as "e-stop" in short.
Q: What colour is required for e-stop buttons?
A: The button itself shall be red and the background (if there is one) shall be yellow.
EN ISO 13850, 4.3.6.
Q: Is it required to stick a E020 pictogram in the vicinity every time an e-stop device is installed?
A: No, categorically speaking, this is not a product safety requirement per 2006/42/EC Machinery Directive. Thus machine manufacturers are not obliged to do so. However, if the workplace requires additional means to indicate e-stop locations due to poor visibility, then with a risk based approach they might be required.
Q: At what height emergency stop devices (intended for hand operation) shall be positioned from reference plane?
A: 0,6 - 1,7 m.
EN ISO 13850, 4.3.2., EN 60204-1, 10.1.2.
Q: Do e-stops always have to be dual channel?
A: No, unless a type C standard requires that way. Cat 1, PL c is adequate.
EN ISO 13850, 4.1.5.1.
Q: For e-stop buttons, are protective shroulds prohibited?
A: No, but other requirements still apply, such as ability to activate with palm of the hand.
EN ISO 13850, 4.3.1
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Q: Are any symbols or texts required to identify e-stop devices?
A: No, the colour coding itself acts as adequate identification means. On the contrary, one should not mark the button or the yellow background with any text or symbol.
EN ISO 13850, 4.3.7
Q: Can we regard e-stops as the primary risk reduction measure in the risk assessment.
A: No. E-stops are not primary risk reduction measures. They never modify the "probability of occurence" factor of the risk and they usually do not modify the "severity of the possible harm" factor of the risk. One shall take the design measures and and then implement e-stop functions as complementary measures.
EN ISO 13850, 4.1.1.3.
Q: Can we use e-stop devices as an alternative to LOTO?
A: No.
EN ISO 4.1.1.2.
Q: How many emergency stop device is required on a X-metre long production line?
A: It depends on the machine type, thus type C standard. For example for packaging machines, at least one e-stop device is required within a walking distance of no more than 5 m along the external guards.
EN 415 5.14.5.
Q: How many emergency stop device can be wired in series?
A: There is no such a limit from functional safety point of view. Many of them can be wired in series as the voltage drop allows.
Q: How can we verify that e-stop devices are compliant:
A: E-stop devices shall comply with EN 60947-5-1, EN 60947-5-5 and EN ISO 13850. See an example declaration of conformity snip below.
#emergencystop
Sr. Regional Engineering Manager & Bar Raiser at Amazon
1 年Thanks, Ahmed! Very good insights. I like that you de-mystify the codes to make it clear for all. I'll ask you few more questions offline for my education which you may be interested in adding in your next FAQ! Looking forward for the next articles maybe about maintenance safe access, Storage systems, machine protection. Cheers
I would almost always use dual channel for an estop with it being the button of last resort, 13850 tells us the minimum we can have for an estop is PL-C, we can also use a symbol for clarification from 60417-5638 (13850 4.3.7)
MD and Principal Consultant at Astute Machinery Consultants Ltd
1 年Emergency stops must have a yellow background….. and that doesn’t mean the barrel of the pushbutton is yellow - it means a yellow background as in the image… Do not use a yellow barrel pushbutton as an emergency stop unless you are going to put a yellow background on the fasica of what you are mounting it on…