Safety Training
Mark Smokowicz Leuze electronic Product Management & Safety Products PM
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What is covered today? • Common safety standards – differences in standards
• • • •
What is Safe Distance? Reach over and under Some definitions Safety Distance calculations – OSHA, EN999, ANSI-RIA
• • • • Mark Smokowicz / LAS
Safe distance example Introduction to Risk Assessment Application example Questions to ask
Common Safety Standards • Occupational Safety and Health Administration – (OSHA) 1910
Machinery and Machine Guarding
• American National Standards Institute – (ANSI) B11.19
Performance Criteria for Safeguarding
• Robotic Industries Association – (RIA) R15.06
Robot Safety Standard
• American Society of Mechanical Engineers – (ASME) B15.1
Safety Standard for Mechanical Power Transmission
• European Standard Acronyms: OSHA ANSI RIA ASME EN CSA Mark Smokowicz / LAS
– (EN954)
Safety of Machinery
• Canadian Standards Association – (CSA) Z434-03
Industrial Robots and Robot Systems General Safety Requirements
What is safe distance? A method of work piece positioning and operator location that eliminates the need for the operator to be in our near the hazardous area during the hazardous portion of the machine cycle CSA Z 432-04 Safeguarding of machinery – ANSI B11-19-2003
All safeguarding devices shall be securely installed and located at a distance such that the hazard cannot be accessed. CSA Z 432-03 Robots – ANSI RIA R15.06-1999
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Safety Distance and Barriers The barrier (and any barrier openings) needs to be sized such that a person cannot reach: » Over » Under » Around » Through and access a Hazard The same for US, Canada and Europe Mark Smokowicz / LAS
“Reach Over” – “Reach Under” CSA Clearance: 20” ANSI RIA Clearance = 18”
Barrier Guards
1.5m (60”) RIA min 1.8m (72”) CSA min
CSA Max: 6” ANSI RIA Max: 12”
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CSA Z434 clause 10.2 ANSI-RIA R15.06
CSA Z432-04 C2 Reaching over protective structures C2.1 General Distance Guards used as perimeter fences should be at least 1800mm high. The data given in Claus C.2.2 for barriers less than 1800mm high should only be used where the 1800 mm height is not reasonably practicable.
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Safety Distances U.S. Safety Distance Formulas Safety Light Curtains must be mounted at a sufficient distance from the pinch point or point of operation hazard to ensure that the machine stops before a person’s hand(s), arm(s), or body reaches the hazard. This distance, referred to as the safety distance, must be properly calculated prior to determining the safety light curtain protective height and mounting the light curtains on the machine. Failure to properly calculate this safety distance may result in operator injury. Note: Regardless of the calculated safety distance, Safety Light Curtains should never be mounted closer than 6 inches from the point of operation or pinch point hazard. ref. EN999 100mm min (4”) In the United States there are two formulas that are used to properly calculate the safety distance. The first, the OSHA formula, is the minimum requirement for the calculation of the safety distance. The second formula, is the ANSI formula, which incorporates additional factors to be considered when calculating the safety distance. Mark Smokowicz / LAS
Dpf Depth Penetration Factor • Maximum travel towards the hazard within the presence sending safeguarding devices (PSSD) field that may occur before a stop is guaranteed • It is possible that you can reach through the light curtain a SHORT distance
Acronyms: AOPD PSSD OS Mark Smokowicz / LAS
• Depth penetration factors will change depending on the resolution of the device or minimum object sensitivity (OS)
Resolution of AOPD Resolution (d) AKA Object Sensitivity (Os)
Resolution (d) = pitch (p) + lens diameter (Ø) d=p+Ø Channel
Channel
Ø
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p
Dpf, Depth Penetration Factor based on ANS-RIA
Light Curtain
Light Grid
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Dpf, Depth Penetration Factor (OS) < 2.5”, Vertical Field For ANS-RIA, CSA
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PSSD Resolution (mm)
Dpf
Dpf
(mm)
(in)
14
24.22
.95
20
44.62
1.75
30
78.62
3.09
40
112.62
4.43
Safe distance calculations OSHA version
Ds = 63 x Ts where:
• Ds = min safe distance between safeguarding device and the hazard (inches)
• 63 = constant, speed of hand/arm when body is stationary, use 63 in/s
• Ts = total stopping time of all the devices in the safety circuit, measured in seconds.
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Safe distance calculations ANSI RIA version
Ds = K x (Ts + Tc + Tr) + Dpf where:
• Ds = min safe distance between safeguarding
device and the hazard (inches) • K = constant, speed of hand/arm when body is stationary, 63 in/s • Ts = stopping time of the machine/equipment (wc)
• Tc = stopping time of the control system (wc) • Tr = response time of the safeguarding device and it’s interface • Dpf = Depth penetration factor Mark Smokowicz / LAS
Safe distance calculations EN99 version
S = (K x T) + C where:
• S = min safe distance between safeguarding
device and the hazard (mm) • K = constant, speed of hand/arm when body is stationary, use 2 m/s • T = t1 + t2 + t3 • t1: response time of the AOPD • t2: response time of the safety interface • t3: response time of the machine
• C = 8 x (d-14) • d = resolution of the AOPD (14 to 40mm)
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Safe distance calculations Ds = 63 x Ts Ds = K x (Ts + Tc + Tr) + Dpf AN S
S = (K x T) + C What to do….so , let’s see the differences?
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I?
O
EN
A? H S
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Safe distance calculations Example: A light curtain application has; o o o o
a response time of 15 ms a machine stopping time of 180ms braking response time of 40ms and a 3.2 inch depth of penetration
Assume a 14mm resolution device Let’s divy this up, solve and compare Mark Smokowicz / LAS
Stopping distance examples Example: A light curtain application has; a response time of 15 ms, a machine stopping time of 180ms, braking response time of 40ms and a 3.2 inch depth of penetration
ANSI version Ds = K x (Ts + Tc + Tr) + Dpf Ds = 18.0”
OSHA version Ds = 63 x Ts Ds = 14.8” Mark Smokowicz / LAS
EN999 version S = (K x T) + C
S = 18.5”
Stopping distance examples
18.5 18 14.8
0 Mark Smokowicz / LAS
5
10
15
20
EN999 ANSI-RIA OSHA
Calculating min Safe Distances
Channel
Stepping behind protection using master and slave units (different resolutions possible).
S
Minimum Safe Distances must be calculated for each segment. Mark Smokowicz / LAS
Safeguarding devices used horizontally Direction of approach parallel to the sensing plane of the AOPD Relationship between height of the sensing plane above ground and resolution of the AOPD:
H = 15 x (dmax - 50) [mm]
d = resolution of the AOPD H = height of the AOPD above ground
dmax = H/15 + 50 [mm]
Minimum safety distance S:
S=K xT+C S
K = 1.6 mm/ms T = tAOPD + tInterface + tMachine in ms
d
(< 850 mm) C = (1200 + 0.4 H) in mm Channel
H* Using EN999 Mark Smokowicz / LAS
H < 1000 mm H < 300 mm is considered not to allow crawling underneath
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Area Scanner Safety Distance EN-954
S = (K x T) + C
= K = T = in C ms = Cmin = SFT = field S
Safety distance in mm 1.6 mm/ms tAOPDDR+tInterface + tMachine 1200 – 0.4 x H in mm 850 mm Depth of protection
Hmin = 15 x (d 50) H = Heights of scanning plain d = Resolution of AOPDDR d Hmin == 70 300mm mm Hmax = 1000 mm
S SFT
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H
Web based tools
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Calculation wizards
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Introduction to Risk Assessment
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Safety related parts of machine control EN 954-1 General schematic representation of a machine
signalling display warning
actuators control device
data storage
and logic or analogue
data processing
operatormachine interface
sensors, safety devices
power control elements (contactors, valves, etc.) machine actuators (engines, cylinders)
power transmission elements working parts Mark Smokowicz / LAS
hard guarding
Risk reduction remaining risk
risk without any safety measures maximally permissible risk risk without safety related parts of machine control
risk level necessary reduction of risk
real reduction of risk
part of risk reduced by safety related parts of control Mark Smokowicz / LAS
part of risk reduced by design measures
Risk elements
Risk
Severity
referring to the considered danger
the possible damage by the considered danger
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is a function of
Probability of damage occurrence: and
- frequency and duration of the danger exposure - possibility of avoidance or limit of damage
Risk elements
severity of the injury
• slight • severe
exposure in danger area
• rarely, short • frequent, long
possibility of avoidance
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• possible • rarely possible
Risk levels EN 954-1
S1
I P1 F1
S2 F2
P2 P1
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III IV V
Severity of injury S1: slight injury (reversible) S2: severe irreversible injury or one or more persons or death of a person
Frequency, duration of exposure Possibility to withhold
Frequency, duration of exposure
Severity of injury
P2
II
F1: rarely to repeated and/or short duration F2: frequent to permanent and/or long duration
Possibility to withhold from exposure to hazard P1: possible by certain conditions P2: rarely possible
Risk reduction index CSA Z434-03
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Safeguard selection matrix CSA Z434-03
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Example EN 954-1 B 1 2 3 4
S1 F1 S2 F2
Result:
P1 P2 P1 P2
Category: _____
The dangerous event is the uncontrolled movement of the press from standstill or a delayed stopping of the machine. This event can cause severe injuries or at worst, lead to death. In this example, it is assumed that the user stays frequently in the danger zone. Since the pressing is a very fast process, the dangerous situation can hardly be avoided.
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Types of AOPD applications Making a danger point safe
Access guarding
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Safeguarding an area
Perimeter guarding
Questions to ask •
To determine resolution to use – Finger safe – Hand safe – Access/area
•
What are you interfaced to? – Solenoid/starter – Safety PLC
•
integrated muting lamp, sensors safety switches
Cables, special mounting considerations? – High vibration – Washdown applications – Ease of wiring
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relay output pnp safety outputs
Special functions required? – Muting – Interlocks
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14/20mm 30/40mm 50/90mm, multibeam, laserscanner
anti-vibration brackets IP68 tubes MIN connectors/cables
What was covered today? • Common safety standards – differences in standards
• • • •
What is Safe Distance? Reach over and under Some definitions Safety Distance calculations – OSHA, EN999, ANSI-RIA
• • • • Mark Smokowicz / LAS
Safe distance example Introduction to Risk Assessment Application example Questions to ask
Thank You for Your Interest in Safety Products of Leuze electronic
Mark Smokowicz / LAS