Optical detectors for combustible gas detection provide an increasingly popular alternative to traditional pellistor-based combustible gas detectors. One reason for their popularity is the ease of implementation in Safety Instrumented Systems (SIS) intended for high availability and Safety Integrity Levels (SIL).

This article describes the fundamental operation of optical gas detectors with the purpose of explaining the issues important to high availability and SIL.

When a jury in the Supreme Court of Victoria found Esso guilty of 11 criminal charges under the Occupational Health and Safety Act, it was essentially passing judgement on the company's management performance. It found that the company had failed, in several ways, to provide and maintain a safe workplace.

Calculating the flow rates for accidental discharges can be confusing. Here, we'll discuss a standard set of equations for a variety of scenarios to help guide you through the process.

Tank blanketing, or padding, refers to applying a cover of gas over the surface of a stores commodity; usually a liquid. Its purpose is either to protect or contain the stored product or prevent it from harming personnel, equipment, or the environment. In most cases the blanketing gas is nitrogen, although other gases may be used.

Part 1 of this series on rupture disks for Process Engineers covered why you use a rupture disk and when you might want to use this device. Part 2 discussed how to size the rupture disk. Part 3 discussed how to set the burst pressure. Part 4 discussed how temperature and backpressure affects the rupture disk specification and the relief pressure in the system. Part 5 discussed the Relief Valve/Rupture Disk combination. In this part, I conclude the series with a discussion of the rupture disk specification.

Part 1 of this series on rupture disks for Process Engineers covered why you use a rupture disk and when you might want to use this device. Part 2 discussed how to size the rupture disk. Part 3 discussed how to set the burst pressure. Part 4 discussed how temperature and backpressure affects the rupture disk specification and the relief pressure in the system. In this part, I will discuss the Relief Valve/Rupture Disk combination.

Part 1 of this series on rupture disks for Process Engineers covered why you use a rupture disk and when you might want to use this device. Part 2 discussed how to size the rupture disk. Part 3 discussed how to set the burst pressure. In this part, I will discuss how temperature and backpressure affects the rupture disk design. Subsequent parts will include the Relief Valve/Rupture Disk combination, how to specify the rupture disk and some discussion on the type of rupture disks you can purchase.

Part 1 of this series on rupture disks for Process Engineers covered why you use a rupture disk and when you might want to use this device. Part 2 discussed how to size the rupture disk. In this part, I will cover how to set the burst pressure. Subsequent parts will include temperature and backpressure affects, the Relief Valve/Rupture Disk combination, how to specify the rupture disk and some discussion on the type of rupture disks you can purchase.

Part 1 of this series on rupture disks for Process Engineers covered why you use a rupture disk and when you might want to use this device. This part will discuss how to size the rupture disk. Subsequent parts will include how to set the burst pressure, the Relief Valve/Rupture Disk combination, how to specify the device and some discussion on the type of rupture disks you can purchase.

This is a real story. A rupture disk manufacturer presented a seminar to a group consisting of junior and more senior level process design engineers (yours truly included) with a few instrument engineers thrown in. After about an hour of hearing terms such as bursting pressure, tolerance, manufacturing range, etc., and discussions on the mechanical aspects that differentiate the various types of rupture disks, the seminar ended with many of those attending just shaking their heads. Most of the attendees just wanted to learn how to specify this item so the instrument engineer can buy one or the manufacturer can tell you what is needed.

What can go wrong in a chemical facility? Plenty! A report in the August 2000 issue of CEP¹ shows that operator error or poor maintenance was the leading of cause of accidents for unfired pressure vessels eight years running.

As the title of this column implies, I intend to present various topics related to Process Engineering Design based on my knowledge and experiences. I will convey what approaches I think you should be taking.