Probe Newsletter

Probe - Vol. 14, No. 2, Second Issue 2007

Vigilant Ventilation

Key to mitigating carbon monoxide hazard

Most of us are familiar with the safety concerns regarding carbon monoxide (CO). I have worked with CO for nearly 30 years as a first responder, investigator, researcher, rules and standards developer, and more. I could go on ad infinitum about CO – what it is, how it is produced – but I want to focus on two things: prevention and diagnostics. (If you are interested in more information about CO, you can contact almost any gas utility or state health department, and they will have free brochures or fact sheets.)

Prevention is, by far, the best way to address CO safety. And it's relatively simple. Burning fossil fuels can produce CO; ergo, don't burn fossil fuels without proper ventilation. Here are a few important reminders:

  • Don't run your car or any other combustion engines in the garage, even with the door open. I've conducted extensive research on this. For example, running your car in the garage, with the door open, for less than a minute, especially on a cold day, can result in more than 1,000 parts per million of CO. This is an extremely dangerous concentration. Back the car out right away after you start it, and leave the garage door open for a few minutes before you drive away.
  • Have your fuel-burning appliances checked annually by a qualified technician. Most of the incidents I have seen are ultimately the result of poor maintenance. I know the excuses for this: "Out of sight, out of mind," "It has worked fine for years," etc. Believe me – you should fit this into your schedule.
  • Install a UL-listed CO alarm near the bedrooms on each level of your home.

Diagnosing CO problems, unlike preventing them, is seldom a simple task. More often than not, a CO incident is the result of two or more simultaneous failures. For example, if a properly installed appliance is making CO, it will vent to the outdoors. It could go on this way for years, if not checked, and may not pose an immediate threat. However, if a bird or other creature finds its way into the vent, that CO could then be forced into the building, and the results could become tragic in a very short period of time.

For this reason, a successful investigation requires extensive knowledge of appliance installation and operation, construction codes, ventilation, combustion air, makeup air, building dynamics and more. On top of that, having the appropriate and calibrated tools, as well as the knowledge of how and when to use them is critical.

The bottom line: Invest in the maintenance of your fuelburning appliances and equipment, and follow safe use practices. If you are concerned that you may have a CO problem, be sure to call on a qualified technician to investigate – and ask questions.

Matt Wilber,
Gas Application Specialist

Gas Pump Safety

New danger when filling up

The American Petroleum Institute says we pump some 400 million gallons of gasoline for motor fuel per day in the United States. Considering gasoline's volatile and flammable properties, it is remarkable there are not more reports of fires or explosions at filling stations.

They do occur, however, and many are due to static electricity. As wellknown as these hazards are, if you would like a refresher, there is an excellent 10-minute free video download, including actual dramatic gas station security camera footage, at www.opw-fc.com.

A new threat to gas pump safety has been developing recently that is unrelated to static electricity. Many pay-at-the-pump gas stations now are programmed with a maximum dollar amount at which the pump will automatically shut off. However, many such dispensers are not equipped with the special nozzle that automatically closes when the pump stops. (Essentially all nozzles in current use at filling stations are designed to close when the tank fills, a different situation.)

It would therefore be possible for a customer to fill until the authorizedsale limit, at which fuel flow stops, and then return the nozzle to the dispenser while it is still open. The next unwary customer – it could be you – might then remove the nozzle from the dispenser, turn on the pump and get covered with gas.

If you use pay-at-the-pump, avoid this potential disaster by always doing two things: First, before removing the nozzle from the dispenser, check to be sure the operating lever on the nozzle is in its closed or relaxed position and not held open by the latch. Second, insert the nozzle in the tank filler pipe before turning on the pump.

In a society powered by vehicles, many of us will fill our gas tanks hundreds of times during our driving lifetime. Paying attention to safety can help ensure that we can look forward to our next drive in the country.

Bill Sutherland,
P.E., Electrical Engineer

Avoid Quality Qualms

Document and qualify vendors' products

Note: This is the fourth article in a four-part series in which a Crane Engineering team member presents quality assurance recommendations for manufacturers. You may download the first three articles here.

Previous "Quality Qualms" articles have focused on quality issues in vendor-supplied rubber and polymer seal materials, choosing the proper material or coating to combat corrosion, and structural materials qualification. This may beg the question, Are there general quality control practices that should be in place that could apply to all these types of materials?

The answer is yes. There are general principles on which to build a quality control program, helping to preempt certain product issues. Many large companies, and regulated companies such as medical device manufacturers, already have these practices and more in place. However, for smaller and medium-sized companies, just following the basics of such larger QC programs can mean the difference between a successful product launch and an unacceptable amount of parts failures.

Documentation is the key. Lot information and manufacturing date records of parts or materials supplied to you should be recorded for all parts used in a device. This could be done using a system as simple as a paper file, or for more complex records, you could turn to a computer spreadsheet or database program to enhance searchability. That way, any issues that may arise that are suspected to have been caused by failure of these parts or materials can be traced to the lot used. If it is determined that a product issue happened with a change in constituent material lot, having a retained sampling from a previous lot will be useful for comparative purposes.

Qualifying the product used in your device is a good start to an effective QC program as well. Request samples from several different lots for a specific part or material and determine consistency of the vendor's product across lots.

This can be done with physical or chemical testing using the material or part specification as a guideline. Widely varying results and a fairly loose specification can be an indication you may want to search elsewhere for this part.

So where should the testing be performed? Third-party test facilities such as those experienced in ASTM and ISO standardized methods are a good place to start. The Internet is a helpful resource for researching testing facility capabilities, as many laboratories list the types of work they do and the standardized methods they perform. A reliable vendor may also be able to recommend a competent test facility – just be sure it is an independent test facility.

In summary, many materials and parts will go into any product or device, and all should be tested and documented regularly. While that ends up being a lot of work, it will likely prevent or at least help solve long-term issues that may arise in your product.

Mike Frencl,
Analytical Chemist

Cross Sections

Welcome, Kerri. Kerri Schnell joined Crane Engineering Oct. 1 as chemistry technician. Working with analytical chemist Mike Frencl, she assists with testing for industrial and forensic projects in our in-house laboratory. Kerri brings more than six years' experience to her new position. She previously served as a forensic chemist for Twin Cities area testing firms, where she performed highly complex lab tests and quantitative analyses using chromatography and mass spectrometry. Earlier, she worked for a major food manufacturer as a lab assistant in the company's biotechnology development center and also as a quality control lab assistant. In 2004-2005, Kerri completed a forensic anthropology internship at the Museum of Man in San Diego. She holds a bachelor of science degree in cellular biology from St. Cloud State University, St. Cloud, Minn., and a master of forensic science degree, specializing in criminalistics, from National University, San Diego. Recent Presentation. Scott Sollars, P.E., spoke on "A Case Study in Mechanical Engineering/Fire Investigation" at the quarterly meeting of the Minnesota International Association of Arson Investigators on Sept. 12. Continued Growth. Crane Engineering is seeking to expand its consulting team. It currently is searching to fill a mechanical engineering position. If you would like more information, please visit CraneEngineering.com/news/ or contact Robin Krier, robink@CraneEngineering.com.