Topic: Safety Systems

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Just How Safe Are Those "Standards-Based" Systems in Your Enterprise?
Why Should I Care if the OPC Product that I Use Has Been through Certification?

Gas Blending Control; Pipe Schedule and Control Valve Size
Any Thoughts on Where to Go for Reference Material and/or Subject Matter Experts for Help with Controls Engineering Project? Is It Mandatory That Pipe Line Schedule Be Mentioned for Control Valve Sizing?

Blocking and Tackling Are Still Required Skills
It Is Sometimes Easier to Get Classes on Advanced Process Control Than on the Basics of General Instrumentation and Control

Rethink Mass Notification
Properly dealing with emergencies demands integration of plant systems.

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White Papers: In Depth Research

Predicting Control Valve Noise in Gas and Steam Applications: Valve Trim Exit Velocity Head vs. Valve Outlet Mach Number
Author: Joseph Shahda, Dresser Masoneilan
Posted: 03/18/2010
Predicting and managing control valve noise has long been an important consideration in gas and steam applications, with the dual goals of protecting workers from potential auditory damage and preventing excessive vibration that could destroy equipment and piping, possibly leading to a catastrophic failure.

At first glance, it may seem that a logical way to achieve these goals would be to limit valve trim exit velocity head to a maximum of 480 kilopascals (kPa), and this indeed is how some have addressed the issue. In practical application, however, it is an oversimplified approach that, in many cases, will not produce the desired results. First, it typically requires the use of expensive multi-stage or multi-turn trim designs, which can cost up to 30 percent more than a simpler solution. More importantly, it also can create a false sense of safety.

This article will explain why the focus should instead be on keeping the valve outlet Mach number low. Practical examples will be used to illustrate that:
- Even if the trim exit velocity head is kept below 480 kPa, valve noise can be unacceptably high if the valve outlet Mach number is high.
- Even if the trim exit velocity number is above 480 kPa, valve noise can be kept to acceptable levels - without using costly trim designs - if the valve outlet Mach number is kept low.

Personnel Functional Safety Certification: Not All Programs Are Created Equal
Author: Exida
Posted: 03/05/2010
As production runs ever closer to equipment and facility operating limits and new plants come on line in expanding and developing economies, the pressure to design and operate systems more safely and economically is increasing. A key to meeting this goal is having competent people who are knowledgeable and experienced in applying the IEC 61508 and IEC 61511 / ISA 84 functional safety standards. To develop and measure an individual's safety engineering competence, several personnel functional safety certification programs have been created. This paper will discuss why these programs are needed and the benefits they deliver to individuals and companies alike. It will also review the characteristics and differences of the various certification programs on the market today, things to watch out for, and some important questions to ask when selecting a certification program.

Low Voltage MCC Technology Helps Reduce Arc-Flash Hazards and Minimize Risks
Author: Rockwell
Posted: 02/08/2010
Selecting the right MCC equipment leads to improved plant safety, helping protect people and capital investments.

Measures to increase equipment and personnel safety in manufacturing are reflected in new approaches and technologies designed to help minimize the risk of workplace dangers. One rapidly growing area of focus is reducing the potentially serious hazards associated with arc-flash events. This white paper examines the causes of arc flash, discusses the standards guiding arc-flash safety and details the role arc-resistant motor control centers (MCCs) play in helping contain arc energy. It also highlights the key features of an effective arc-resistant MCC design.

Managing safety hazards and reducing risks are top priorities for manufacturers across all sectors of industry. With a multitude of potential dangers and new ones continuously emerging, companies must be diligent in their ongoing efforts while considering new approaches and technologies to improve plant safety. One rapidly growing area of focus is implementing techniques and practices designed to reduce hazards and minimize risk for workers who must enter an area with an electrical arc-flash potential.

Safety & Automation System (SAS) - How the Safety and the Automation Systems Finally Come Together as an HMI
Author: Ian Nimmo
Posted: 01/06/2010
Today we have clear guidelines on how the Safety Instrumented Systems (SIS) and basic Process Control Systems (BPCS) should be separated from a controls and network perspective. But what does this mean to the HMI and the control room design?

Where do Fire & Gas Systems fit into the big picture and what about new Security and Environmental monitoring tasks?

What does the Instrument Engineer needs to know about operators and how systems communicate with them.

The evolution of the control room continues as Large Screen Displays provide a big picture view of multiple systems. Do rules and guidelines exist for this aspect of independent protection layers? What are today's best practices for bringing these islands of technology together.

This paper will review the topic and provide advice on a subject on which the books remain silent. Today's practices are haphazard and left to individuals without a systematic design or guidance.

Over the past 20 years the Safety System and the Automation system have been evolving separately. They use similar technologies, but the operator interface needs to be just one system. Unfortunately, due to the nature of the designs, this is not the case.

The automation system has been evolving since the introduction of the DCS and many Human Factor mistakes have been made. As we move towards new standards such as ISA SP 101 a more formal approach to HMI design is being taken.

The past widespread use of black backgrounds which cause glare issues in the control room and are solely responsible for turning the control room lights down to very low levels, or in some cases off, are being replaced with grey backgrounds and a new grayscale graphic standard replacing bright colors for a more plain grayscale scheme only using color to attract the operators' attention.

In having strong compliance schemes that restrict color usage to just a handful of colors, restricting the use of some colors that are reserved for important information such as alarm status, it appears that the automation system is being standardized and is starting to take advantage of new technology available to control room designers such as large screen displays.

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