12. Process Automation and Safety Instrumented Systems

Question 1

What is PSM?

Answer 1

Process Safety Management

A systematic approach to identify, evaluate, and mitigate hazards resulting from complex industrial processes.

Question 2

What three Canadian regulators address the objectives of process safety management?

Answer 2

Unlike the USA where OSHA had federal jurisdiction to enforce PSM regulations, Canada has provincial jurisdiction for OHS.

-The National energy Board
-The Alberta Energy Regulator
-The BC Oil and Gas Commission
each address objectives found in OSHA PSM.

Question 3

List two quantitative and two qualitative benefits for businesses implementing PSM systems.

Answer 3

Process Safety Management systems provide:

(quantitative) Risk Reduction. There are fewer minor and catastrophic incidents with their associated costs and repercussions
(quantitative) Sustained value. PSM systems help produce higher quality, reliable products. Often resulting in improved efficiency and lower costs.
(qualitative) Corporate responsibility. Demonstration of corporation doing the right thing
(qualitative) Business flexibility. PSMs lead to safer operations and the ability to carve new paths within industry.

Question 4

What four factors have driven the need for improvement in process safety management of highly hazardous chemicals?

Answer 4

Critical events

Changing regulatory focus

Stakeholder (public) attention

Multinational corporations

Question 5

How did Canada respond to the 1984 Bhopal, India, gas leak?

Answer 5

Formation of the MIACC (Major Industrial Accident Council of Canada).

Government, industry, and labour experts to examine whether a similar accident could occur in Canada.

This is considered a conservative approach, and it was because there was already oversight by industrial associations and it was thought that a less threatening approach would be more effective.

Question 6

Differentiate process controls and safety controls in automated industrial processes.

Answer 6

Process controls are micromanagers that are constantly monitoring and adjusting to maintain quality production.

Safety controls are macro-managers that passively monitor and only act in the event of a problem to intervene. This may involve stopping part or all of the industrial process.

Problems with process controls are easy to identify, because there are immediate repercussions. Problems with safety controls are hard to identify, because they may show no symptoms until there is an emergency.

Question 7

What is a safety instrumented system in the context of automated industrial processes?

Answer 7

Safety Instrumented Systems (SIS) are systems that monitor the industrial process for problems and initiate control devices to stop processes when measurements are out of the safety range.

SIS are comprised of:

• sensors
• computing device
• actuators/control devices

formerly called safety shutdown systems

Question 8

Define and differentiate the prevention layers and mitigation layers in the LOP concept.

Answer 8

LOP = Layers of Protection concept.

Prevention layers are the controls that prevent an incident.
Mitigation layers are the controls that reduce the severity of an incident.

An emergency stop button is a prevention layer, and the venting system to remove any harmful gasses that were produced before the emergency stop is a mitigation layer.

Question 9

What is a SIF in a SIS? Context, automated process safety.

Answer 9

SIS = Safety Instrumented System
SIF = Safety Instrumented Function

SIF are the actions taken by the SIS to bring a process to a safe state.

Question 10

SIS, SIF, and SIL … explain

Answer 10

SIS = Safety Instrumented System
SIF = Safety Instrumented Function
SIL = Safety Integrity Level

The SIS is the overall safety system that monitors processes and intervenes when measurements fall outside of acceptable range.
The SIS is comprised of 1 or more SIFs, the actions taken to bring the process to a safe state.
Each SIF has a SIL, a measurement of the probability that the SIF will fail.

Question 11

Differentiate between ALARA and ALARP.

Answer 11

ALARA = As Low As Reasonably Achievable
ALARP = As Low as Reasonably practical

North American terminology vs European.
Same shit.

Question 12

What process industry workplaces require a SIS?

Answer 12

Determined by hazard identification and risk assessment.
SIS are expensive. The more SIFs there are and the higher the SIL of each SIF, the higher the cost.

Companies must determine their risk levels and evaluate the controls in place to determine IF a SIS is needed etc.
Due diligence and balance of reasonable practice vs cost.

Question 13

What is an industrial robot?

Answer 13

An automatically controlled, reprogrammable multipurpose manipulator, programmable in three or more axes, which may be fixed in place or mobile for use in industrial automation applications.

Question 14

Differentiate AGVs and SDVs.

Answer 14

AGV = Automated Guided Vehicle
SDV = Self-Driving Vehicle

AGVs are mobile machines that are automatically guided in their movements (floor markings, magnets, lasers, etc)

SDVs are autonomous mobile machines that have their own sensors & computer controllers to navigate and make decisions.

Question 15

On industrial robots, what are EOATs and arms?

Answer 15

EOAT = End-Of-Arm-Tool aka End Effectors

EOAT are the tools connected to the end of a working arm.

Arms are the part of a robot that gives the range of motion.

Question 16

On industrial robots, what are EOATs and arms?

Answer 16

EOAT = End-Of-Arm-Tool aka End Effectors

EOAT are the tools connected to the end of a working arm.

Arms are the part of a robot that gives the range of motion.

Question 17

List important differences between AGVs and SDVs.

Answer 17

1, Pathways
AGVs follow pre-determined pathways. SDVs determine own path from point A to B.

2, Infrastructure
AGVs require some form of infrastructure for guidance. SDVs need only a map to identify key locations.

3, Cost
AGV infrastructure is expensive, adding units is less so.
SDV cost is almost all in the unit.

Question 18

What are the three most common types of accident involving industrial robots?

Answer 18

• Worker struck by arm or EOAT
• Worked contact with EOAT (injury determined by tool type)
• Worker trapped/crushed between arm/EOAT and another structure

Question 19

What are the three most common types of accident involving industrial robots?

Answer 19

• Worker struck by arm or EOAT
• Worked contact with EOAT (injury determined by tool type)
• Worker trapped/crushed between arm/EOAT and another structure

Question 20

What is a singularity in the context of industrial robots?

Answer 20

A singularity refers to the many potential correct movements/positions that a robot could take. This can result in seemingly erratic movements.

Example, the tool must be in a specific location, but the arm can achieve this in many different configurations. Therefore the arm continuously moves through every possible configuration.

Question 21

How are industrial robots regulated in Canada?

Answer 21

Most regulators, including the BC OHSR, make CSA Z434 a requirement.

Regulations are often slightly out of date with regards to robot safety, and so due diligence requires that companies ensure they are up to date with safety standards beyond the regulated minimum.

Question 22

What are the four points in a the life of an industrial robot where safety hazards may occur?

Answer 22

• Installation
• Programming/teaching
• Operation
• Maintenance

Question 23

What are maximum, restricted, and operating spaces in regards to industrial robots.

Answer 23

The range of motion for a robot can be categorized into three spaces.

Maximum - the total possible ROM of the arm and EOAT

Restricted - the possible ROM of the arm and EOAT after barriers and physical restrictions are considered.

Operating - the ROM of the arm and EOAT as determined by the programming.

Question 24

What are three advantages of PSM?

Answer 24

Process Safety Management advantages

• Effective and systematic identification of hazards and risk assessments
• A clear systematic method of accident investigation
• High level of training for workers

Question 25

List the basic components found on a typical fixed industrial robot with an articulated arm.

Answer 25

end-effector (EOAT)
arm
base
power supply
controller
associated machines and tools within the system