Functional Safety

As systems rely more and more on sophisticated hardware and software, safety is increasingly dependent on the relationship between products and their responses to inputs. Functional safety depends on equipment or a system operating correctly in response to its inputs. Neither overall product safety nor functional safety can be determined without carefully evaluating a product's systems as a whole and assessing the environment with which they interact.

A functional safety evaluation includes:

• Software
• Hardware
• Environmental Factors, such as EMC
• Safety lifecycle management processes

Why evaluate your product for functional safety?

A functional safety assessment can determine that your products meet standards and performance requirements created to protect against potential injury or death. There are many reasons to seek functional safety certification including:

• Customer requirements - Your own customers may demand a functional safety evaluation before purchasing equipment
• Market acceptance - Marketing products as having a functional safety certification differentiates your products and strengthens your product's competitiveness in the marketplace
• Legislative requirements - Some European Directives require a functional safety evaluation
• Regulations - Some regulatory bodies such as Occupational Safety and Health Administration (OSHA) require or encourage functional safety evaluation
• Trade unions - Some unions require or encourage use of functional safety certified products in the workplace
• Insurance companies - Your customers' insurers may require a functional safety evaluation before the customer installs the equipment in the workplace or the insurer may provide discounted premiums to customers that use products evaluated for functional safety

UL deliverables

• Advisory services  that can provide assistance with:
  • Validation Plans
  • Safety Requirements Specification (SRS)
  • Failure Modes and Effects Analysis (FMEA)
  • Failure Modes, Effects, and Diagnostic Analysis (FMEDA)
  • Safety Plans
  • Software FMEA/Software Hazard and Operability (HAZOP) Analysis
  • Integrated test plans, including identifying appropriate environmental conditions for testing (such as humidity, EMI, vibration, etc.)
  • Safety manuals
  • Safety cases, including risk analysis
  • Functional safety management plans
  • Calculation or verification of Safety Integrity Levels (SIL), Performance Levels (PL), or Classes, etc.
• Functional Safety Component Recognition Mark
• Functional Safety Listing Mark
• Functional Safety Test Reports
• MTTFd Calculation and B10d Testing Services
• 3-year Functional Safety Certificate
• Type examination reports
• Training Courses
  • IEC 61508 Introductory Training
  • IEC 61800-5-2 Functional Safety in Motor Drives Training
  • ISO 13849 and IEC 62061 Training

Functional safety standards

UL can evaluate safety-related products to a variety of standards, including but not limited to:

• ASME A17.1: Safety code for elevators and escalators
• CSA C22.2 NO 0.8: Safety functions incorporating electronic technology
• EN 50271: Electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen
• EN 954 - Safety of machinery and safety-related parts of control systems
• IEC 60730-1 - Automatic electrical controls for household and similar use
• IEC 61496 - Evaluation of safety-related electrosensitive protective equipment
• IEC 61508 - Functional safety of products, components and systems. Evaluation covers electrical/electronic/ programmable electronic (E/E/PE) safety-related systems and assessment of the proper safety integrity levels (SILs) of your product or system
• IEC 61511 - Safety for instrumented systems for the process industry sector
• IEC 61800-5-2 - Safety of adjustable speed electrical power drive systems
• IEC 62061 - Safety of machinery and functional safety of safety-related electrical, electronic and programmable electronic control systems
• ISO 10218 - Safety requirements for robots used in industrial environments
• ISO 13849 - Safety of machinery and safety-related parts of control systems
• ISO 26262 - Road vehicles -- Functional safety
• UL 1998 - Assessment of software safety and evaluation of computer/software-controlled products
• UL 991 - Assessment of controls that employ solid state devices and are intended for specified safety related protective functions

Products UL evaluates for functional safety

Safety-related products, such as light curtains or safety-programmable controllers, carry greater implications for human safety and equipment damage than products typically used in an industrial environment. A functional safety assessment help establish that standards and performance requirements designated to protect against potential injury or death are met. Common products that receive functional safety evaluations include:

• Burner management systems
• Combustion controls
• Electrosensitive equipment such as laser scanners, light curtains and machine vision equipment
• Elevator components
• Gas detection equipment
• Motor drives
• Process control equipment
• Programmable components
• Programmable logic controllers (PLCs) and programmable automation controllers (PACs)
• Robotics and accessories

Additional resources

• Consistency in SIL and PL Justification
• Functional safety brochure
• Functional safety sell sheet
• Functional safety white paper
• The Transition from EN 954 to EN ISO 13849-1
• Understanding Key Changes in IEC 61508:2010 white paper
• "Using Hazard Based Engineering Standards to Guide Software Design" by Anura Fernando
• Listen to a free recorded webcast: "Functional Safety: What it is, Why it's important and How to comply"
• Download the slides from the webcast "Functional Safety: What it is, Why it's important, and How to comply"
• Listen to a free recorded webcast: "Functional Safety: Importance. Compliance. Benefits"
• Download the slides from the webcast "Functional Safety: Importance. Compliance. Benefits"
• Listen to a free recorded webcast: "IEC 61508 2nd Edition: Get Educated. Get Compliant"
• Download the slides from the webcast "IEC 61508 2nd Edition: Get Educated. Get Compliant"