Tuesday, August 16, 2016

Monitoring and Control of Carbon Monoxide Emissions in a Parking Structure

Parking lot CO2 Monitor
Parking lot CO2 Monitor
(courtesy of CONSPEC)
Reprinted with permission by CONSPEC


Carbon monoxide (CO) emissions from motor vehicles can have detrimental effects on the air quality inside subterranean parking garages. CO, an odorless, tasteless and colorless gas, is the leading cause of accidental poisoning deaths in the United States. The Centers for Disease Control estimates that CO poisoning claims nearly 500 lives and accounts for more than 15,000 visits to emergency rooms annually. When not properly ventilated, CO concentrations can build to toxic levels. Also when CO emissions fill a space, the oxygen in that space is depleted, causing asphyxiation.

In an underground parking garage without adequate ventilation, CO can easily exceed NIOSH and OSHA recommendations, and put workers, tenants and commuters at severe health and safety risks. Several states have passed laws to protect parking garage personnel from CO exposure.

Ventilation systems, therefore, are a must for today’s mixed use underground parking facilities, but they can be costly to operate 24 hours, seven days a week. This is why mechanical contractors and HVAC specialists are increasingly specifying CO monitoring and ventilations systems for both new and existing parking structures.

CARBON MONOXIDE SENSING TECHNOLOGIES

Not all CO sensors are alike. Electrochemical sensing technology provides many advantages over the older semiconductor (“solid state”) sensors or infrared sensors. Electrochemical sensors offer high resolution (≤ 0.5 ppm), a linear signal, long-term stability (≥5% over the lifetime of the sensor) and immunity to false alarms caused by “nuisance gases.”

The best CO sensing technologies will also alert facility and emergency personnel, via cell phone, in the case of dangerous concentrations of CO. Use of CO monitoring and ventilation can not only protect human health, but also can help prevent fire, as increased CO levels can sometimes predict the imminent threat of fire.

While inadequate ventilation can drastically increase the risks of liability, continuous operation of ventilation systems can
be costly. To minimize heat loss in winter, as well as conserve energy used by the ventilation fan motors, some parking garage owners began to operate ventilation systems only during peak traffic times, that is, during the morning and evening rush hours. This, however, failed to take into account instances

in which a car was left idling or parking patterns varied from the norm. This explains the growing trend toward installation of CO monitoring and ventilation control systems.

AN ALTERNATIVE TO CONTINUOUS VENTILATION

To minimize health and safety liability issues, some garage owners decided to simply run ventilation systems continuously, but this created other problems. Jeff Aiken, a project manager with Professional Mechanical Contractors, Inc., notes that continuous fan operation can mean continuous annoyance for tenants in apartments or condominiums close to fans.

“CO emissions also create tremendous liability issues,” Aiken noted, “but continuous operation is not a good solution. Installing a gas detection solves this dilemma.”

In response to the energy crisis in California in the 1980s, Conspec Controls developed a combined CO monitoring and ventilation system using electrochemical sensing technology. For maximum cost efficiency in new construction, the design should include an integrated CO monitoring and ventilation system.

The Conspec P2621 is often specified due to its large area of coverage. For instance, in a typical garage with ten-foot ceilings, one unit will cover 10,000 square feet, while competing systems require two units in the same space.

Saturday, July 16, 2016

Examining the User Interface of the SensAlert ASI Gas Detector

The Sensidyne SensAlert ASI provides enhanced protection and dependability for critical safety applications where personnel, processes, and facilities are at risk. The third party certified SIL-2 SensAlert ASI offers dependability and versatility while remaining the easiest to install, commission, operate, and maintain.

The video below demonstrates the setting menu and the operator interface.

The product is third-party certified to IEC61508 Level 2 (SIL-2) for both hardware and software with certification to global hazardous area and performance standards. The Test-on-Demand feature with on-board gas generator provides remote functionality checks with generated gas while Predictive Sensor End-of-Life Indication provides advanced warning of impending sensor failure.

SensAlert ASI is a universal instrument platform for toxic & combustible gas detection and oxygen monitoring. Intrinsically safe or explosion proof installation configurations with options for remote sensors and gassing, duct mount, and sample-draw maximize application versatility. Intrinsically safe or explosion proof installation configurations for remote sensors and gassing, duct mount, and sample-draw maximize application versatility. The sensor head accepts all Plus Series sensor technologies – infrared, catalytic bead, and electro-chemical. Assignable and configurable relays together with communication options provide broad flexibility. The SensAlert ASI I.S. sensor head can be remote mounted up to 100 feet (30m) from the transmitter providing a useful option to position the transmitter in a personnel-accessible location while positioning the sensor closer to potential hazards.

Thursday, June 30, 2016

Food Processing: Belt Scales Improve Tomato Processor Efficiency and Productivity

Belt Scales Improve Tomato Processor Efficiency
Belt Scales Improve
Tomato Processing
The following post is a case history on using alternative technology to improve large scale food preparation process.  You'll read about how belt scales outperformed legacy equipment for a tomato peeling process and increasing yield.

Application:

A tomato processor located on the Paciļ¬c coast uses the latest technologies in peeling, dicing, and packaging tomatoes. They were preparing to replace some of their older weigh feeders because of declining performance. One of their main concerns with installing new weigh feeders was the cost of moving the existing conveying systems in order to accommodate new weigh feeders.

See the document below for the full case history:

Wednesday, June 22, 2016

2 Wire, 3 Wire, and 4 Wire RTD Sensor Connections

Industrial temperature transmitters
Industrial temperature
transmitters (courtesy of
Siemens)
Industrial temperature transmitters are devices that measure the temperature of a process and provide a measurable output over some desired temperature range. Industrial temperature transmitters primarily use either of two popular temperature sensors - the thermocouple or the RTD (resistance temperature detector). The RTD changes resistance as process temperature changes, while a thermocouple provides a changing micro-voltage with process temperature change. RTDs are inherently more accurate, but require excitation voltage. There are three style RTD's - 2-wire, 3-wire, and 4-wire.


Proper connections for all three types of RTD sensor to a user- configurable transmitter are shown in the following illustrations:

proper wiring of RTDs
Proper wiring of RTDs
It is critically important to note that the common connections shown by the symbols for 3- and 4-wire RTD sensors represent junction points at the sensor; not terminals jumpered by the technician at the time of installation, and not internal jumpers inside the transmitter. The whole purpose of having 3-wire and 4-wire RTD circuits is to eliminate errors due to voltage drop along the current-carrying wires, and this can only be realized if the “sensing” wire(s) extend out to the RTD itself and connect there. If the transmitter’s sensing terminal(s) are only jumpered to a current- carrying terminal, the transmitter will sense voltage dropped by the RTD plus voltage dropped by the current-carrying wire(s), leading to falsely high temperature indications.

Click here for more information on industrial RTDs and temperature transmitters.

For more information about any temperature measuring application, contact:
Ives Equipment
www.ivesequipment.com
(877) 768-1600

Some of above content taken from Lessons In Industrial Instrumentation by Tony R. Kuphaldt – under the terms and conditions of the Creative Commons Attribution 4.0 International Public License.

Wednesday, June 15, 2016

Combustion Analyzer Adds Higher Level of Safety by Measuring O2, Combustibles, and Methane

WDG-VThe reliable identification of low combustion oxygen in a fired heater or boiler has always been critical to the effectiveness of the Burner Management System for proper control and safety.

Low emission burners and aggressive firing control points to achieve increased efficiency and emission reductions have driven the industry to tighter control measures. But tighter control measures also hold a greater potential for combustion events. Reducing the risk of a combustion event has become a priority and has led to the implementation of Safety Instrumented Systems (SIS). This additional layer of safety is added to the Basic Process Control System.

The WDG-V has been designed to provide an additional layer of safety with the measurement of excess O2, Combustibles and Methane and by using these measurements to ensure the safe operation of the Burner Management System.

WDG analyzers are based on a zirconium oxide cell that provides a reliable and cost-effective solution for measuring excess oxygen in flue gas as well as CO and methane levels. Information from the Gas Analyzer allows operators to obtain the highest fuel efficiency, while lowering emissions for NOx, CO and CO2. The zirconium oxide cell responds to the difference between the concentration of oxygen in the flue gas versus an air reference. To assure complete combustion, the flue gas should contain several percent oxygen. The optimum excess oxygen concentration is dependent on the fuel type (natural gas, hydrocarbon liquids and coal).