Instrumentation and Plant Safety Case Study: Refinery Explosion

A case study of the 2005 BP refinery explosion in Texas City, TX. This video recaps the events and circumstances leading up to a catastrophic explosion. Contributing factors include inadequate level and safety instrumentation, as well as breakdowns in safety monitoring and standard operating procedures. This video, courtesy of the Chemical Safety Board (csv.gov) is an excellent educational reference and should be viewed by engineering, maintenance, and plant management personnel everywhere.

Instrument Specialties, Inc.
http://isi.group
407-324-7800

Instrument Specialties, Inc. - ISI Technical Group

Instrument Specialties is in the business of helping customers improve and implement their processes and applications. A professional agency with a focused, creative, and aggressive staff, ISI takes a long term relationship approach to business.

https://www.isisales.com
407-324-7800

Groundwater Monitoring Instrumentation

The Level TROLL groundwater monitoring instrument can be
suspended in a well and log temperature, pressure, and level.
Image courtesy In-Situ

In-Situ specializes in the manufacture of instruments used for monitoring groundwater and other water testing functions. In the fields of aquaculture, remediation, energy, mining and research, In-Situ is regarded as an innovator, providing reliable top quality water monitoring equipment.

The company's Level TROLL line of water level data loggers are specifically intended for aquifer characterization. The instruments provide continuous level, pressure and temperature readings when suspended in a well. The battery operated units can function for very long periods, holding up to 260,000 data points.

The Level TROLL Instrument is completely sealed and contains no user-serviceable parts. The instrument includes pressure and temperature sensors, a real-time clock, microprocessor, sealed lithium battery, data logger, and memory. Instruments are available in a variety of pressure (depth) ranges with vented and non-vented sensors. Placement within a well can be accomplished with In-Situ's Rugged Cable System, custom built for each application to provide direct reading operation. The cable assembly includes titanium twist-lock connectors, desiccant to prevent condensation in the vent tube, shielded connecting cable, and a placement grip for secure deployment. A second option for instrument deployment is suspension via a polyurethane coated stainless steel cable for applications that do not require direct reading, only data logging.

There are several models from which to choose, and other products suitable for groundwater monitoring throughout many industries. Share your water monitoring requirements of all types with instrumentation specialists. Combine your own knowledge and experience with their product application expertise to develop effective solutions.

Well Water Level Monitor from Instrument Specialties, Inc.

In-Situ, Inc. - Water Quality Instrumentation

In-Situ manufactures instruments for measuring water quality and quantity throughout industrial, commercial, institutional, and municipal settings. Watch the video to see broad range of scientific instruments designed and manufactured by the company for laboratory, process, and field use.

Get more detailed information, or share you water quality measurement challenges with a product application specialist.

Guide to Industrial Electrical Grounding

Electrical Grounding

Acromag, a manufacturer of industrial I/O solutions, recently produced a 3-part series on the best practices of grounding electrical equipment. For your convenience, this post combines all three parts of the white paper here into a single document below.

When wiring or connecting circuits, electrical equipment, and electrical instruments, there is a connection that you probably don’t give much thought to, and one that consequently reigns as one of the greatest sources of instrument error and malfunction. That connection is Ground.

Electrical systems must be grounded in order to work properly. The earth often serves as an ideal ground because of its large mass and ability to absorb charge, but ground can be any electrical connection that is able to freely conduct electricity, and grounding a circuit does not always refer to making a physical connection to earth ground.

To learn much more, please read the following document.

The Complete Acromag Guide to Industrial Electrical Grounding from Instrument Specialties, Inc.

Helpful Hazardous Area Definitions for Process Control Instrumentation

Courtesy of SOR Pressure, Temperature, and Level Instruments

SOR Explosion Proof
Pressure Switch

Hazardous Area Classification

Hazardous Areas are locations where the potential for fire or explosion exists because of gases, dust, or easily ignitable fibers or flyings in the atmosphere.

In North America, hazardous area classification is separated by classes, divisions, and groups to define the level of safety required for equipment installed in these locations. Classes define the general form of the flammable materials in the atmosphere. Divisions define the probability of the presence of flammable materials. Groups classify the exact flammable nature of the material.

In Europe and countries outside of North America, classification of hazardous areas is accomplished differently. Zones are used to define the probability of the presence of flammable materials. Protection Types denote the level of safety for the device. Groups classify the exact flammable nature of the material. These groups are separated differently than North American Groups. Temperature Identifications convey the maximum surface temperature of the apparatus based on 104° F (40° C) ambient. These temperature codes are selected carefully not to exceed the ignition temperature of the specific gas or vapor to be encountered in the application.

Some hazardous area classifications are not shown here. For further detailed information, see specific standards published by approval organizations.

Classifications Inside North America

Classes
Class I	Flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures.
Class II	Combustible or conductive dusts are present.
Class III	Ignitable fibers or flyings are present, but not likely to be in suspension in sufficient quantities to produce ignitable mixtures. (Group classifications are not applied to this class.)

Divisions
Division 1	The substance referred to by class is present during normal conditions.
Division 2	The substance referred to by class is present only in abnormal conditions, such as a container failure or system breakdown.

Groups
Group A	Acetylene
Group B	Hydrogen (or gases of equivalent hazard)
Group C	Ethylene (or gases of equivalent hazard)
Group D	Gasoline (or gases of equivalent hazard)
Group E	Metal Dust
Group F	Coal Dust
Group G	Grain Dust

---

Classification Outside North America

Zones
Zone 0	Area in which an explosive gas-air mixture is continuously present or present for long periods.
Zone 1	Combustible or conductive dusts are present.Area in which an explosive gas-air mixture is likely to occur in normal operation.
Zone 2	Area in which an explosive gas-air mixture is not likely to occur, and if it occurs it will only exist for a short time.

Protection Types
		Zone
d	Flameproof (Explosion proof) Enclosure	1,2
e	Increased Safety	1,2
ia	Intrinsic Safety	0,1,2
ib	Intrinsic Safety	1,2
o	Oil Immersion	2
p	Pressurized Apparatus (Purged Apparatus)	1,2
q	Powder Filling (Sand Filling)	2
m	Encapsulation	1,2
n	Normally Nonsparking and/or Nonincendive Circuits)	2

Temperature Codes
	°F	°C
T1	842	450
T2	572	300
T3	392	200
T4	275	135
T5	212	100
T6	185	85

Groups
Group I	For application in below ground installations (mines) where methane (firedamp) and coal dust may be present.
Group IIA	For application in above ground installation where hazards due to propane may exist. This group most closely matches the North American Group D.
Group IIB	For application in above ground installations where hazards due to ethylene may exist. This group most closely matches the North American Group C.
Group IIC	For application in above ground installations where hazards due to hydrogen or acetylene may exist. This group most closely matches the North American Groups A and B.

A Compact, Rugged and Explosion Proof Industrial Pressure Switch

Mini Hermet

Need a robust, explosion proof pressure switch with a small footprint? The SOR "Mini Hermet" is your answer. This pressure switch is ideally suited for a variety of process applications in hazardous locations and hostile environments where stainless steel exterior parts are required and where space is limited. Basic models with standard wetted parts are normally suitable for air, oil, water and non-corrosive process fluids.

The pressure sensing assembly is similar to a conventional pressure switch. The main difference is that the switching element assembly is hermetically sealed in an explosion proof steel capsule. Switching elements are SPDT or DPDT.

The pressure sensing element is a force-balance, piston-actuated assembly. The sensing element is sealed by a flexible diaphragm and a static o-ring. There are only three wetted parts in this arrangement: a pressure port, a diaphragm and an o-ring. A wide selection of wetted parts materials for media compatibility and containment are available.

For more information contact:

Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
phone 407.324.7800
fax 407.324.1104
e-mail: offices@isisales.com

Basic Lesson on Flow Control Valves

For anyone interested in flow control basics, control valve basics, check valve basics and many other technical topics, videos are available on YouTube from the Columbia Gorge Community College. The teacher's name is Jim Pytel and he does an excellent job. Here's a video tutorial Flow Control Valve basics.

Welcome to the Process Instrumentation and Control Blog of Florida

Process Control Professionals

We're building this blog to provide people interested in process control instrumentation, industrial valves, measurement and control a place to learn interesting applications, products, and basic knowledge.

The markets we are attempting to connect with are the powergen industry, mining, water and wastewater treatment, agricultural, chemical, food & beverage, pharmaceutical and OEMs.

We'll do our best to provide weekly posts to keep the blog fresh and informative, and a place you'll want to check back with regularly.

The world of industrial control is changing rapidly in the United States, partially due to rapidly changing technology, or environmental and legislative pressures. We hope to provide helpful information, based on current realities, that will help solve real world process control problems.