Jun
3
Integrated Safety Instrumented Systems and Distributed Control Systems - Are They a Good Idea?
Filed Under Management | Comments Off
Samuel P. Whittle asked:
For those of you who have been entrusted with the task of selecting a safety instrumented system for use in your plant, often run into a perplexing question. Should I go for an integrated Safety Instrumented System, which will be totally different from my Distributed Control system (or DCS for short)? Or should I select one of the newer “integrated systems”, that comprise of both the Distributed Control System and a Safety Instrumented System in one package?
A Safety Instrumented System (or SIS) is a special kind of control system that is used for the safety critical parts of process plants, turbo machinery, boilers and other machinery or equipment that has to be controlled with a very high degree of reliability in order to run it safely, as well as bring it to a safe state if something goes wrong. Emergency Shutdown Systems (ESD for short), can be considered a subset of the SIS category of control systems.
On the other hand DCS (Distributed Control Systems) are those control systems that are used for normal control and monitoring operations of process plants, oil refineries, oil & gas production platforms, power plants and so on. The DCS is the main system that measures, monitors and controls various process parameters like flow, temperature, pressure and so on. In standards related literature, this system is also referred to as the BPCS (short for Basic Process Control System).
In the view of the standards bodies (like IEC and ISA), these two systems have to be completely separate, as these safety instrumented systems have to be dedicated to controlling only the safety critical parts of the plant .The ordinary DCS cannot be said to be robust, fail-safe and sure to operate the safety critical instruments at all times. This distinction between the DCS and SIS, led to separate markets for both types of systems with separate suppliers for both, initially. Thus companies like Triconex, HIMA, Pilz and ICS Triplex were the traditional vendors of these Safety Instrumented Systems, whereas the BPCS or DCS market belonged to the companies like Emerson, ABB, Honeywell, Yokogawa and Invensys.
This obviously, meant that now, if a plant had instruments and controls that were designated as safety critical, it necessarily required a separate SIS; the DCS would not do at all because of what the standards state. Thus now, one control room had two control systems, completely different as chalk and cheese. The SIS had separate power supply (or a UPS), separate panels, monitoring stations, separate programming software and of course totally separate hardware from the DCS. The same Instrument engineer who maintained the instruments and controls of this process plant, now had to be adept at both systems simultaneously. Plant modifications and changes were a pain as any change had to be implemented in both systems, with a lot of testing to ensure that the original interlocks and loops worked as designed to.
Making the two systems communicate with each other, also proved not so simple, since even after DCS vendors had come out with open systems, the Safety Instrumented System vendors were reluctant to migrate to such systems, due to the extensive proof testing required to ensure that the “open” systems were bug free.
Hence, most instrument engineers in these situations started wishing for a new deal, whereby both the SIS and the DCS could talk to each other seamlessly (even while remaining separate to conform to the standards) . Also, what if they could share a common engineering /programming platform as well? That would be the icing on the cake!
The DCS vendors sensed this mood of the users and many of them came out with “integrated” DCS/SIS systems, where the DCS and SIS controllers are different, but part of the same overall system. Some recent examples are Emerson’s Delta V with SIS and Siemens Safety Integrated system. These reportedly have become popular, due to the fact that most of these integrated systems have got third party (most commonly TUV) certificates for the SIS part, so users can have a worry free installation of these for safety critical applications. However, I have not yet seen any debate in the technical media, regarding this issue. Are these systems doing great, or are users now longing for the earlier separate DCS/SIS systems? I think we need some more time and more data, to arrive at any definitive conclusion. The advantages of an integrated DCS/SIS are obvious, as stated above. The disadvantages are somewhat less obvious. One disadvantage is that if the SIS portion is really easy to program, then there is a chance that unauthorized users (say a savvy DCS operator) might end up changing protected settings like interlock bypasses and setpoints, which is really dangerous. Plus the thought of having an SIS with a standard “open” OS like Windows, is rather uncomfortable, as the last thing one wants is a system freeze during an emergency.
Only time will tell, if the integrated SIS/DCS systems were a better choice than the stand-alone SIS, as then we would have enough data to have a balanced view.
Gilbert
For those of you who have been entrusted with the task of selecting a safety instrumented system for use in your plant, often run into a perplexing question. Should I go for an integrated Safety Instrumented System, which will be totally different from my Distributed Control system (or DCS for short)? Or should I select one of the newer “integrated systems”, that comprise of both the Distributed Control System and a Safety Instrumented System in one package?
A Safety Instrumented System (or SIS) is a special kind of control system that is used for the safety critical parts of process plants, turbo machinery, boilers and other machinery or equipment that has to be controlled with a very high degree of reliability in order to run it safely, as well as bring it to a safe state if something goes wrong. Emergency Shutdown Systems (ESD for short), can be considered a subset of the SIS category of control systems.
On the other hand DCS (Distributed Control Systems) are those control systems that are used for normal control and monitoring operations of process plants, oil refineries, oil & gas production platforms, power plants and so on. The DCS is the main system that measures, monitors and controls various process parameters like flow, temperature, pressure and so on. In standards related literature, this system is also referred to as the BPCS (short for Basic Process Control System).
In the view of the standards bodies (like IEC and ISA), these two systems have to be completely separate, as these safety instrumented systems have to be dedicated to controlling only the safety critical parts of the plant .The ordinary DCS cannot be said to be robust, fail-safe and sure to operate the safety critical instruments at all times. This distinction between the DCS and SIS, led to separate markets for both types of systems with separate suppliers for both, initially. Thus companies like Triconex, HIMA, Pilz and ICS Triplex were the traditional vendors of these Safety Instrumented Systems, whereas the BPCS or DCS market belonged to the companies like Emerson, ABB, Honeywell, Yokogawa and Invensys.
This obviously, meant that now, if a plant had instruments and controls that were designated as safety critical, it necessarily required a separate SIS; the DCS would not do at all because of what the standards state. Thus now, one control room had two control systems, completely different as chalk and cheese. The SIS had separate power supply (or a UPS), separate panels, monitoring stations, separate programming software and of course totally separate hardware from the DCS. The same Instrument engineer who maintained the instruments and controls of this process plant, now had to be adept at both systems simultaneously. Plant modifications and changes were a pain as any change had to be implemented in both systems, with a lot of testing to ensure that the original interlocks and loops worked as designed to.
Making the two systems communicate with each other, also proved not so simple, since even after DCS vendors had come out with open systems, the Safety Instrumented System vendors were reluctant to migrate to such systems, due to the extensive proof testing required to ensure that the “open” systems were bug free.
Hence, most instrument engineers in these situations started wishing for a new deal, whereby both the SIS and the DCS could talk to each other seamlessly (even while remaining separate to conform to the standards) . Also, what if they could share a common engineering /programming platform as well? That would be the icing on the cake!
The DCS vendors sensed this mood of the users and many of them came out with “integrated” DCS/SIS systems, where the DCS and SIS controllers are different, but part of the same overall system. Some recent examples are Emerson’s Delta V with SIS and Siemens Safety Integrated system. These reportedly have become popular, due to the fact that most of these integrated systems have got third party (most commonly TUV) certificates for the SIS part, so users can have a worry free installation of these for safety critical applications. However, I have not yet seen any debate in the technical media, regarding this issue. Are these systems doing great, or are users now longing for the earlier separate DCS/SIS systems? I think we need some more time and more data, to arrive at any definitive conclusion. The advantages of an integrated DCS/SIS are obvious, as stated above. The disadvantages are somewhat less obvious. One disadvantage is that if the SIS portion is really easy to program, then there is a chance that unauthorized users (say a savvy DCS operator) might end up changing protected settings like interlock bypasses and setpoints, which is really dangerous. Plus the thought of having an SIS with a standard “open” OS like Windows, is rather uncomfortable, as the last thing one wants is a system freeze during an emergency.
Only time will tell, if the integrated SIS/DCS systems were a better choice than the stand-alone SIS, as then we would have enough data to have a balanced view.
Gilbert
Feb
16
Workers’ Compensation Safety Issues: the 5/4 Method of Communicating Safety to a Diverse Workforce
Filed Under Management | Comments Off
Robert Elliott asked:
As indicated in previous articles, the field of workers’ compensation risk management is not only many faceted and complex but also presents various challenges.
Communicating safety issues effectively to a diverse workforce represents one of these challenges. As a risk management consultant for many years, I’ve gathered solid information and experience on the best way to communicate safety and workers’ compensation messages to a large and diverse workforce, including organizations with thousands of employees with diverse backgrounds and many different job descriptions.
We can call this the Five/Four Method: 5 Safety Communication Techniques and 4 Safety Message Formats. Before beginning, identify your target audience and the safety message you want to give.
However, the most important thing an employer must do before implementing any safety communication program is meet with employees and supervisors to discover their ideas on what needs to be communicated and how best to do it.
Five Safety Communication Techniques
First: Identify the specific message you want to communicate.
Example: Is the message about getting employees to work more safely around certain equipment?
Or is it to provide information on steps to take if they are injured?
Second: Identify the skill set and grade level of your audience.
Example: A message to the vice president level on how to improve commitment to the safety program would be presented differently than instructions to first-line employees on how to report an accident.
A general rule of thumb for thinking about language levels is to keep in mind the Wall Street Journal is written at a first-year college level, while the Reader’s Digest is written at a sixth grade reading level.
Third: Consider the job functions and how best to get your message across.
Example: Some employees might spend most of their work day in an office or one specific area of a plant. Others may spend it working in different areas of the plant or facility. Still others may spend their day driving from location to location. It’s a good idea to tailor your safety message to the types of safety issues more likely to effect those employees and areas of work.
Fourth: Identify the languages your employees speak. Don’t assume they will be just English and/or Spanish. There can be many other languages. In many areas of the country there are large contingents of Russian speaking workers just to mention one. In addition, there are differences within languages, such as Cuban Spanish and Puerto Rican Spanish.
It would not be too far off the mark to suggest management survey their workers’ languages and provide all safety messages as appropriate. This is especially true if non-English speaking workers are employed in high-risk safety areas.
Fifth: Consider the work environment. If you have congenial workforce, don’t use a heavy-handed communication style. Save it for a workforce where there may be a lot of discontent and resentment.
Four Safety Message Formats
Now it’s time to look at a number of ways to present your safety message.
1. Wallet Cards: A heavy-duty wallet card is one of the most effective tools to give your employees to convey your safety message. Each card is printed with important safety information and/or accident reporting information.
A wallet card for accidents would provide information on where to seek treatment in the workplace, where to report the accident, where to file a workers’ compensation claim (usually with the workers’ compensation coordinator), the importance of returning to work as quickly as possible, etc. The card also has contact information for the workers’ compensation office and other parties involved in the process. (E.g.: TPA, insurance rep, etc.).
Information is printed in English on one side and Spanish on the other (or another prevailing language from your workforce). Supervisors receive different cards outlining their role in responding to accidents.
2. Safety Sheets: A laminated one-page safety sheet is another good option. Post in each work area using a permanent non-removable method. Use bright-colored paper to draw all employees’ attention to it, but allowing the supervisor to distinguish this post from other posted documents. Direct the employees’ attention by saying: “Please read the safety information on the orange sheet.”
3. Pictograms in one-page safety sheets are very useful in communicating with people who have lower level language skills or who speak different languages. An example might be pictograms on proper lifting techniques.
Each month a different safety sheet on a different safety topic is posted: on lifting correctly; on fall protection; slips and falls, etc. Also, give each employee an individual copy for permanent reference.
4. Safety Packets: For employees who drive all day, prepare safety packets of information to be stored in a glove compartment. The packet also contains a disposable camera for use at the site to record an accident, along with an accident reporting form.
For more information and tools, see WC Cost Reduction Tips. There are several free forms and tools on the site.
Note: Do not use this information without independent verification. All state laws are different. Consult with your corporate legal counsel before implementing any cost containment programs.
Robert Elliott, senior vice president, Amaxx Risks Solutions, Inc. has worked successfully for 20 years with many industries to reduce Workers’ Compensation costs, including airlines, health care, manufacturing, printing/publishing, pharmaceuticals, retail, hospitality. Contact him at: Robert_Elliott@reduceyourworkerscomp.com or 860-553-6604.
©2008 Amaxx Risk Solutions, Inc., All rights reserved under International Copyright Law
Tyrone
As indicated in previous articles, the field of workers’ compensation risk management is not only many faceted and complex but also presents various challenges.
Communicating safety issues effectively to a diverse workforce represents one of these challenges. As a risk management consultant for many years, I’ve gathered solid information and experience on the best way to communicate safety and workers’ compensation messages to a large and diverse workforce, including organizations with thousands of employees with diverse backgrounds and many different job descriptions.
We can call this the Five/Four Method: 5 Safety Communication Techniques and 4 Safety Message Formats. Before beginning, identify your target audience and the safety message you want to give.
However, the most important thing an employer must do before implementing any safety communication program is meet with employees and supervisors to discover their ideas on what needs to be communicated and how best to do it.
Five Safety Communication Techniques
First: Identify the specific message you want to communicate.
Example: Is the message about getting employees to work more safely around certain equipment?
Or is it to provide information on steps to take if they are injured?
Second: Identify the skill set and grade level of your audience.
Example: A message to the vice president level on how to improve commitment to the safety program would be presented differently than instructions to first-line employees on how to report an accident.
A general rule of thumb for thinking about language levels is to keep in mind the Wall Street Journal is written at a first-year college level, while the Reader’s Digest is written at a sixth grade reading level.
Third: Consider the job functions and how best to get your message across.
Example: Some employees might spend most of their work day in an office or one specific area of a plant. Others may spend it working in different areas of the plant or facility. Still others may spend their day driving from location to location. It’s a good idea to tailor your safety message to the types of safety issues more likely to effect those employees and areas of work.
Fourth: Identify the languages your employees speak. Don’t assume they will be just English and/or Spanish. There can be many other languages. In many areas of the country there are large contingents of Russian speaking workers just to mention one. In addition, there are differences within languages, such as Cuban Spanish and Puerto Rican Spanish.
It would not be too far off the mark to suggest management survey their workers’ languages and provide all safety messages as appropriate. This is especially true if non-English speaking workers are employed in high-risk safety areas.
Fifth: Consider the work environment. If you have congenial workforce, don’t use a heavy-handed communication style. Save it for a workforce where there may be a lot of discontent and resentment.
Four Safety Message Formats
Now it’s time to look at a number of ways to present your safety message.
1. Wallet Cards: A heavy-duty wallet card is one of the most effective tools to give your employees to convey your safety message. Each card is printed with important safety information and/or accident reporting information.
A wallet card for accidents would provide information on where to seek treatment in the workplace, where to report the accident, where to file a workers’ compensation claim (usually with the workers’ compensation coordinator), the importance of returning to work as quickly as possible, etc. The card also has contact information for the workers’ compensation office and other parties involved in the process. (E.g.: TPA, insurance rep, etc.).
Information is printed in English on one side and Spanish on the other (or another prevailing language from your workforce). Supervisors receive different cards outlining their role in responding to accidents.
2. Safety Sheets: A laminated one-page safety sheet is another good option. Post in each work area using a permanent non-removable method. Use bright-colored paper to draw all employees’ attention to it, but allowing the supervisor to distinguish this post from other posted documents. Direct the employees’ attention by saying: “Please read the safety information on the orange sheet.”
3. Pictograms in one-page safety sheets are very useful in communicating with people who have lower level language skills or who speak different languages. An example might be pictograms on proper lifting techniques.
Each month a different safety sheet on a different safety topic is posted: on lifting correctly; on fall protection; slips and falls, etc. Also, give each employee an individual copy for permanent reference.
4. Safety Packets: For employees who drive all day, prepare safety packets of information to be stored in a glove compartment. The packet also contains a disposable camera for use at the site to record an accident, along with an accident reporting form.
For more information and tools, see WC Cost Reduction Tips. There are several free forms and tools on the site.
Note: Do not use this information without independent verification. All state laws are different. Consult with your corporate legal counsel before implementing any cost containment programs.
Robert Elliott, senior vice president, Amaxx Risks Solutions, Inc. has worked successfully for 20 years with many industries to reduce Workers’ Compensation costs, including airlines, health care, manufacturing, printing/publishing, pharmaceuticals, retail, hospitality. Contact him at: Robert_Elliott@reduceyourworkerscomp.com or 860-553-6604.
©2008 Amaxx Risk Solutions, Inc., All rights reserved under International Copyright Law
Tyrone