UPGRADING MACHINE SAFETY

DEVICES AND INTERLOCKS

By Paul Malburg

Facility Engineer / Controls Manager

Madico, Inc.

SAFETY CONTROL DEVICES ON OLDER

EQUIPMENT (UPGRADING)

• Introduction

• OSHA Requirements

• Risk Assessment

• Safety Components Options

• Risk Category versus Electrical Rating Category

• Summary & Questions

INTRODUCTIONS

How our company got started doing Risk

Assessments

How safe was our equipment and what is the

meaning of “Control Reliable” circuits

The working relationship between Manufacturer

(End User) and Equipment Vendors

OSHA TERM

“GENERAL DUTY CLAUSE”

Employer shall furnish a place of employment which are free from recognized hazards

Employer will comply with all occupational safety and health standards

Employees shall comply with occupational safety and health standards and all rules, regulations

LAMINATING AND COATING INDUSTRY ARE

COVERED UNDER THE FOLLOWING

STANDARDS, (BUT NOT LIMITED TO)

ANSI B11.19, "Performance Criteria for Safeguarding“

ANSI/ RIA R15.06, "Safety Requirements for Industrial Robots and Systems”

ANSI/ASSE Z244.1, "Control of Hazardous Energy”

NFPA79, “Electrical Standard for Industrial Machinery”

OSHA TERM

“BEST PRACTICE”

The best practices guide is not a standard or

regulation

Safety practices in a manufacturing facility begin

with a Hazard Analysis or Risk Assessment

Three ways to improve safety -- engineering

controls, administrative controls and the use of

personal protective equipment (PPE)

TYPES OF CONTROLS

Physical changes and improvements

made to a machine or workstation.

These include electrical control circuits,

machine guards, isolation devices, and

hazard isolation.

Include, but are not limited to written

procedures and training. Training is the

main tool that ties all safety practices

together.

This is equipment which protects

employees from harm. In terms of

hazard control methods, usage of

personal protective equipment is the

last hazard control.

Personal

Protective

Equipment

Administrative

Engineering

BEST

PRACTICE

HAZARD ANALYSIS / RISK ASSESSMENT

It identifies risks through

observations of the interaction

between the worker, job,

environment and tools. Once

hazards are identified,

management puts controls in place

to prevent, reduce or eliminate them. The benefits of a comprehensive

hazard analysis are improved safety, lower costs and

increased productivity.

RISK REDUCTION CATEGORY

RISK REDUCTION

CATEGORY

SAFEGUARD PERFORMANCE CIRCUIT PERFORMANCE

R1 Hazard elimination or hazard substitution Control reliable

R2A Engineering controls preventing access to

the hazard, or stopping the hazard

interlocked barrier guards, light curtains,

safety mats, or other presence sensing

devices

Control reliable

R2B Single channel with

monitoring

R2C Single channel

R3A Non-interlocked barriers, clearance,

procedures and equipment

Single channel

R3B Simple

R4 Awareness means Simple

ELECTRICAL RATINGS BY CATEGORY

SUMMARY OF REQUIREMENTS BY CATEGORY SYSTEM BEHAVIOUR Notes

CATEGORY B When a fault occurs it can lead to a

loss of the safety function. Category B in itself has

no special measures for

safety CATEGORY 1

As described for category B but with

higher safety related reliability of the

safety related function.

CATEGORY 2

The loss of safety function is

detected and periodically checked

by the machine control system

CATEGORY 3 When the single fault occurs the

safety function is always performed. Multiple faults caused by

a common cause or as

inevitable consequences

of the first fault shall be

counted as a single

fault.

CATEGORY 4

When the faults occurs the safety

function is always performed. The

faults will be detected in time to

prevent the loss of safety functions.

SAFETY COMPONENTS

• Guards Fixed in Place

• E-Stops and Cable pulls

• Tongue Interlock Switches

• Pressure –sensitive safety edges

• E-Stop Safety Relay

• Programmable Safety Controllers

• Safety Programmable Logic Controllers (Safety PLC)

• Pressure Sensitive Safety Mats

• Area Scanners

• Light Curtains

RISK ASSESSMENT

TURRET WINDER SECTION

SEVERITY OF

INJURY

EMPLOYEE

EXPOSURE

AVOIDANCE TO

HAZARD

RISK

REDUCTION

CATEGORY

Serious Injury

More than

First-Aid

Frequent Not Likely R1

Likely R2A

Infrequent Not Likely

R2B Likely

Slight Injury

Less than

First-Aid

Frequent Not Likely R2C

Likely R3A

Infrequent Not Likely R3B

Likely R4

Serious Injury

More than

First-Aid

Frequent Likely R2A

RISK REDUCTION

CATEGORY

SAFEGUARD PERFORMANCE CIRCUIT

TYPE

R1 Hazard elimination or hazard

substitution Control Reliable

R2A

Engineering controls preventing

access to the hazard, or

stopping the hazard

R2B

Single channel

with

monitoring

Single channel R2C

R3A Non-Interlocked barriers,

clearance, procedures and equip. R3B Simple

R4 Awareness means

R2A

Engineering controls preventing

access to the hazard, or

stopping the hazard

Control Reliable

OPTIONS FOR ADDING SAFETY DEVICES TO TURRET WINDER

R2A

Engineering Controls

Control Reliable

Risk Reduction

Dpf Safe Distance (Ds) Ds

DS = [K * (TS + TC + TR)] + DPF

SUMMARY & QUESTIONS