Safety Principles for Machine Design and Risk Assessment
Published by : Industrial Automation
It is important to understand these safety concepts when adding safeguards to machines.
When it comes to keeping people and equipment safe in industrial environments, the plant operator is traditionally responsible for preventing accidents. However, safety norms are changing on a global scale with several countries implementing new safety regulations that add responsibility to the machine builders and designers. If you’re an OEM, you must design safeguards into machines and systems or else get left behind in domestic and global markets.
Not only are international regulations evolving rapidly, so is the technology advancing machine safety. Innovative optoelectronics, sensors, programmable logic and other digital implementations are making machines and systems safer and more intelligent. Whether you’re an MRO or OEM, staying current with machine safety technology and standards is critical. The following principles for machine design and risk assessment can help you keep work environments safe from machine-related hazards
Conduct a risk assessment to identify hazards, risk and harm
A risk assessment will identify hazards associated with machine operation and the potential physical harm or health effects that could result from those hazards. Many IDEC products are designed to address mechanical hazards posed by machine parts, functions or processes. After identifying the potential source of harm, evaluate the potential severity of that harm: Could the machine-related injury result in disfigurement, amputation or death? Your risk assessment should determine how frequently the hazard exposure will occur and the probability of how likely an injury will occur. Note that a risk assessment should be performed by a certified risk assessor.
Risk reduction through safeguarding
Safeguards can include any protection measure that can reduce the risk of harm to personnel. If your risk assessment identifies mechanical hazards in your machine, they can be mitigated through machine design. Safeguards for mechanical hazards can range from a simple gate to guard a machine’s entry point or a two-push safety switch to stop operation, or to more advanced sensing solutions like a light curtain that cannot be thwarted by mechanical means.
Understand global safety standards
Standards establish a minimum level of product safety in a region, either by mandate or recommendation. Machines that comply with appropriate standards provide a means for customers to recognise quality, thereby helping a company reach a wider market and minimise development and testing costs.
European Union standards and performance levels
ISO (the International Organisation for Standardisation) and IEC (the International Electrotechnical Commission) develop and govern standards for machines and electronics. ISO and IEC standards are typically harmonised, and machines that ship to the European Union (EU) must also comply with ISO standards. The jointly issued ISO/IEC Guide 51 establishes a structure that groups specialised safety standards under three tiers: Type A, Type B and Type C.
i. Type A basic safety standards. Contains basic concepts, design principles and general safety aspects that can be applied to all machinery.
ii. Type B generic safety standards pertain to one safety aspect or one type of safeguard that can be used across many machine types.
iii. Type C machine safety standards. Refer to detailed safety standards for a specific machine or group of machines.
ISO 13849-1 performance levels assess risk in machines
1. ISO 13849-1 Performance Levels. For machines, ISO 13849-1 assigns alphameric performance levels according to their qualitative risk for injury severity, frequency and/or exposure to hazard, and the possibility of avoiding hazard or limiting harm. PLa is the lowest risk level, and PLd and PLe indicate a very high risk.
2. ISO 13849-1 Defined Performance Levels comprise an architecture of six categories (“B” and 1 through five, with B being the least safe and 5 being the most safe). Factors include PL levels, diagnostic coverage (DC) and mean time to dangerous failure (MTTFd).
IDEC helps build safety into automated machines and systems
When building safety into a machine, you simply want the best component to address the risks and hazards. The fast-paced world of industrial automation doesn’t slow down while you investigate various products and the safety standards that pertain to many different regions. That’s why you should choose machine safety products from a company whose innovative products comply with global standards, thereby opening markets and opportunities for your machines.
IDEC’s cost-effective safety products offer advanced features to safeguard machines, protect personnel and monitor systems. All our safety products are designed to meet the latest international safety regulations — and can satisfy the ISO/IEC performance level and defined performance level categories you must meet — so you can focus your time on your work while mitigating risks to people and operations. Highlights of our innovative safety product line include:
a. E-stops with exclusive safe break action technology, which reverses the energy direction and uses spring-pressure to guarantee that the NC contacts will open if the emergency switch is damaged or the contact blocks separate due to excessive force.
b. Safety laser scanner – Features a long 5.3-metre protection zone and a very wide range of filtering options to detune the scanner or ignore obstacles.
c. Interlock switches in a wide variety of sizes, contact arrangements and functions to satisfy a broad range of applications.
d. Safety controllers require no programming and can replace up to seven relays to consolidate safety circuits.
IDEC experts can work with your machine to help suggest the right safety product based on your potential hazards and risks. With over 60 years’ experience providing control and automation products, IDEC safety products can make sure your personnel, machines and systems are safe and productive.
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