Understanding Hazmat Placards

Hazmat placards and labels both serve the purpose of communicating hazard information to people but, despite the similarities, there are some important differences between the two as well. The basic difference is this: labels provide identifying information and hazard information about a particular product whereas placards identify the class into which a hazardous material falls. Placards are primarily used in hazardous materials transportation. Labels are designed for the end user.

Placard Appearance

Placards are diamond shaped signs that are placed on each side of trucks that are hauling hazardous materials. Except in the case of small quantities, these placards are required to be displayed whenever the material in question is on board. Their main purpose is to aid those who may be responding in the event of an accident or spill. Fire department personnel, police and hazmat team members can take the information displayed on the placard and cross-reference it to the appropriate section in the Emergency Response Guidebook for guidance on appropriate spill control and safety measures. Materials that require placarding fall into one of nine classes.

Class 1, Explosives

Placards designating explosives are orange in color. Explosives are materials that are capable of producing gas at a temperature, speed and pressure that would cause damage or materials that are designed for pyrotechnic effects. There are six subcategories of explosives ranging from class 1.1, for mass explosion hazards, to 1.9 for insensitive products with no mass explosion hazard.

Class 2, Gases

These placards can be white, green, red or yellow, depending on the type of gas. The gas categories are: toxic, non-flammable, flammable and oxidizers.

Class 3, Flammable Liquids

Placards for flammable liquids are red in color and have a picture of a flame near the top corner. Combustible liquids are also in this class. Normally, a material is considered flammable if it has a flash point below 100 degrees Fahrenheit and combustible if it is below 200.

Class 4, Flammable Solids

This class also includes products that are subject to spontaneous combustion or that are water-reactive. Flammable solids placards are red and white striped. Spontaneously combustible ones are red on the bottom and white on top while blue is for water reactive substances.

Class 5, Oxidizers and Organic Peroxides

These placards are yellow with a flame on top of a circle in the upper corner of the placard.

Class 6, Toxic and Infectious Substances

White placards with black lettering are used for class 6 materials. They also have either a skull and crossbones, for toxics, or a biohazard symbol to indicate infectious materials

Class 7, Radioactive Materials

These placards are either yellow and white or all white and are used for materials affected by the Transport of Nuclear Substances regulations.

Class 8, Corrosives

A material is corrosive if it causes full thickness skin destruction or fails the ASTM corrosion test. The placards have a black bottom with a white top.

Class 9, Miscellaneous Products

Marine pollutants typically fall into this category as do materials that are shipped hot. These placards are also white with black lettering. Marine pollutants are indicated by a picture of a tree and fish. Other miscellaneous placards will have black stripes on the top half.

Why Cabinet Coolers Are Better Than Heat Pipes and Air Conditioners

An industrial cabinet cooler is a way to provide air conditioning to electrical enclosures and purge or cool electronic control panels. They eliminate electronic control downtime caused by dirt, heat and moisture. This is the opposite of other cooling options, such as heat pipes and air conditioners. When weighed against cabinet coolers, air conditioners and heat pipes are considered unreliable. Below are reasons why cabinet coolers are more reliable than heat pipes and air conditioners.

The Problem with Heat Pipes

Heat pipes have many limitations. For example, on hot days the temperature of a room can become almost equal to the temperature of an electrical enclosure, which can prevent heat exchange from occurring. This happens because when rooms and enclosures are nearly the same temperature there isn’t enough difference for heat exchange to occur. So, the cooling capacity is limited by ambient conditions. Heat pipes may also fail if dirt and dust clog the filter.

The Problem with Air Conditioners

Air conditioners have many limitations in industrial surroundings. They are notorious for failing due to dirt and dust clogging the filter. Vibrations from machinery can cause component failures and refrigerant leaks. They require a floor drain because of condensation. Their compressor life is only 2.5 years of continuous operation, and thermostat control can reduce this life even more. Plus, replacing a bad compressor can cost as much as $750. Besides that, they take nearly a day to install, meaning a machine will be halted for that day.

Industrial Cabinet Coolers vs. Heat Pipes vs. Air conditioners

Industrial cabinet coolers stack up well again air conditioners and heat pipes. They use a vortex tube to produce cold air from compressed air, so they have no moving parts. The parts of air conditioners and heat pipes often fail due to clogged filters and mechanical wear. Because cabinet coolers have no moving parts that wear out, they are maintenance free, thus more cost effective than the other cooling options.

Cabinet coolers can be installed within minutes while air conditioners and heat pipes can take hours or even an entire day to install. Coolers also keep panels constantly dry and cool at an average temperature of -6° C while air conditioners have condensation that keep panels moist, and heat pipes are prone to temperature fluctuations and overheating. Overheating of electronics can lead to heat damage to circuit boards and shut downs due to tripped breakers and overloads. However, because industrial coolers maintain a constant temperature machine shut downs, trip-outs and erroneous readings never occur. Visit Pelmar Engineering if you would like to learn more.