Machine Safety / PUWERFor Safety Practitioner

Are you competent?

Are your health and safety specialists actively involved in machine safety?

Do they have the right skills and competences?

Judith Hackitt CBE, HSE Chair

Who am I?

• Certified machine safety expert

• Covered heavy engineering departments

Involved with

• CE Marking and machine risk assessment

• Complex and simple machines

PUWER – Enemy or Friend

Light curtains

Signage

Hierarchy of control

CE Marking Vs PUWER

• CE marking deals with the machine being used for its intended purpose

• PUWER must account for misuse of the machine

• What measures can we apply to all our machines.

• No single way to make every machine safe.

PUWER Primary Objective

“ To ensure that work equipment should

not result in health and safety risks

regardless of its age, condition or

origin”

CE Marking

• And now the Electro-magnetic fields directive

CE marking• demonstrating compliance with the Essential Health and

Safety Requirements;

• carrying out the appropriate conformity assessment procedure;

• drawing up and issue the Declaration of Conformity or Incorporation; and applying the CE Mark.

• Only harmonised standards can be use to demonstrate compliance with the essential health and safety requirements of the machinery directive.

• Alterations log

Definition of a machine

• An assembly of linked parts or components at least one of which moves, with the appropriate actuator, control and power circuits, joined together for a specific application, in particular for the processing, treatment, moving or packaging of a material. And a control system is one that “responds to input signals from the machine, or from the operator, and generates output signals, which make the machine operate in a desired manner”. So if, for example, an operator presses a start button, the control system may respond by closing a contactor and energising a motor.

• Machinery Directive.

Standards • Type A standards

• (Basic safety standards) giving basic concepts, principles for design, and general aspects

• that can be applied to all machinery;

• Type B standards

• (Generic safety standards) dealing with one safety aspect or one type of safeguard that can

• be used across a wide range of machinery:

• Type C standards

• (Machine safety standards) dealing with detailed safety requirements for a particular

• machine or group of machines.

Functional safety

• ISO 13849

• IEC 62061

• Both standards look at the architecture of the safety system

What is needed to establish PL / CAT

EN ISO 13849-1 parameters Meaning

Cat. Category (B, 1, 2, 3, 4), structural setup as the basis for determining a specific PL

PL Performance level (a, b, c, d, e)

MTTFd Mean time to dangerous failure

B10d

Number of cycles with which 10 % of a random selection of the considered abrasion-prone pneumatic or electro-mechanical components have a failure to danger.

DC Diagnostic coverage

CCF Common cause failure

TM Service life, intended usage time (mission time)

Performance Level

S Seriousness of injury S1 Minor (usually reversible) injury S2 Serious (usually irreversible injury including death) Fr Frequency and/or duration of the exposure to the hazard F1 Seldom to not very frequent and/or exposure to hazard is brief F2 Frequent to continuous and/or exposure to hazard is long P Possibility of preventing the hazard or limiting the harm P1 Possible under certain conditions P2 Not really possible

BS EN ISO 13849-1: 2008, 85 pages

CAT

Different stop buttons

• Stop category 0: stopping by immediate removal of power to the machine actuators (uncontrolled stop);

• Stop category 1: a controlled stop with power available to the machine actuators to achieve the stop and then removal of power when the stop is achieved;

• Stop category 2: a controlled stop with power left available to the machine actuators.

However stop category 2 is not usually considered suitable for emergency stops.

Reliability engineering

•A reliable machine is a safe and cost effective machine.

Why bother

Information

• Various SHP online (magazine) articles

• www.machinery-safety-alliance.co.uk

• CE Marking association

• Laidler

• Proctors

• Spierssafety

• www.machinebuilding.net

• www.babt.com