User:Jaysarvage/sandbox/hazchem

The Hazchem (stylised HAZCHEM) code system is a placard system commonly displayed on vehicles, buildings and around facilities where dangerous chemicals and materials are being manufactured, used, transported and/or stored. Hazchem is a portmanteau of "hazardous" and "chemical" and is similar in meaning to the portmanteau Hazmat, combining "hazardous" and "material" which is also often stylised in capitals.

"Hazchem" typically refers to raw dangerous chemicals in bulk but is often interchangeably used with the portmanteau word "Hazmat". Hazmat is used to collectively refer to dangerous substances and other materials (i.e. "HAZMATs") in a fire fighting context, like ammunition, fireworks or aerosol cans, which aren't themselves raw chemical substances but are comprised of chemical substances considered 'dangerous' or present a danger to emergency services and the general public.

Confusion may arise over the naming of the code system as it includes non-chemical substances, like Radioactive materials and "Miscellaneous dangerous goods" which do not specifically refer to chemical substances (e.g. ammunition, fireworks or aerosol cans). Outside fire fighting circles, hazardous chemicals and materials may simply be referred to as dangerous goods.

The Hazchem code system displays crucial information about the identity and hazards associated with the materials. It may also recommend responses to an accident, incident, spill or fire involving the materials. In addition to the system displaying vital information about what hazards such materials pose, the system also includes a non-dangerous goods display to denote that goods in transport are not dangerous in comparison to the dangers that hazardous chemicals or materials might pose. These are typically found on fuel tankers that aren't transporting any hazardous substances. Such Hazchem code placards also include a standard notification to contact the police or fire fighters in case of an emergency, as well as contact information of the manufacturer or supplier of the material for 'specialist advice'.

Hazard class diamond
The Hazchem code system panel includes an easy to recognise symbol or diamond which allows rapid identification of the general nature of the hazards of chemical or material the Hazchem code is describing. This has the advantage of being rapidly identifiable to the general public of what hazards such materials pose, which might not be immediately apparent from alphanumeric codes that emergency responders are trained to find and interpret.

UN Number
Each HazChem placard will have a UN Number displayed in addition to other information in order for the general public to report to emergency services by way of an emergency call or for emergency services personnel to identify what the material is and to customise a response based on more detailed information listed in field guides such as the Emergency Response Guidebook.

Fire fighting methods
The Emergency Action Code (EAC) is a three character alphanumeric code displayed on a Hazchem placard which provides a quick assessment to emergency responders (i.e. fire fighters and police) of what actions to take should the dangerous material become involved in an incident. The Emergency Action Code is characterised by a single number (1 to 4) and either one or two letters (depending on the hazard). The system is not compatible with the ADR Hazard Identification Number (HIN) system, also known as the Kemler Code. Emergency Action Codes denote what actions should be taken in dealing with an incident involving a particular chemical, whereas the Hazard Identification Number only details what the hazards of the chemical are and does not suggest responses unlike Emergency Action Codes.

The initial number displayed is indicative of what type of fire suppressant should be used to prevent the material from igniting or to extinguish a fire threatening to involve the material or which has been caused by the material. The system is designed to rank fire suppression methods in order of suitability, 1 being the lowest, 4 being the highest. Where a higher ranked suppression method is listed, lower ranked methods are automatically excluded. Where the lowest ranked suppression method is listed in the Emergency Action Code, each rank above it is also able to be used where appropriate. For example, a chemical marked with the number 2, suggesting to attack with Fog, the material can be attacked with methods Foam (3) or Dry Agent (4) but not with jets of water (1). The "Dry Agent" method must be used for materials that have an undesirable reaction with water and materials that must not be allowed to come in contact with water, therefore 4 is the highest ranking suppression method as all of the other methods use water in some form.

Some Emergency Action Codes include a bullet (•) preceding the numerical character of the code, which indicates an alcohol resistant foam should be used, as some substances are capable of dissolving and rendering 'normal' fire fighting foam ineffective. However if an alcohol resistant foam is not available, the number denoting the fire fighting method should be used.

Hazchem safety parameters
Hazardous materials are divided into categories each which provides a single method of response when an incident or accident occurs involving the substance. There are two versions of the Emergency Action Codes, originally with eight major categories and four sub-categories, which has since been revised into only eight major classes where one protection clause was removed in the newer system.

Previous code
Under this code, eight 'major categories' existed denoted by a black letter on a white background. Four subcategories existed which specifically highlights what type of personal protective equipment responders must wear when handling the emergency, denoted by a white letter on a black square background, or by enclosing the letter in square braces "[#]" where it is not possible to differentiate colours, word processed documents being one such example. The sub-categories listed in this table are no longer valid and current Emergency Action Codes should be used.

Current code
The newer code uses the same eight major categories but has been revised to remove the sub-categories and therefore the "BA for fire only" protection option, simplifying the code. The change recognises that breathing apparatus should always be used in "significant events" where a hazardous material is involved. This differs substantially from the previous code where emergency responders were permitted under the code to work with S, T, Y and Z without breathing apparatus where fire was not present for short periods of time.

Interpretation
Interpreting the Emergency Action Code is achieved by reading the Emergency Action Code depicted at the incident, matching up the first letter with the letter in the first column of the Emergency Action Code card. The number and bullet (where applicable) denoting what fire fighting response to use is independent of the Emergency Action Code, meaning that fire fighting methods and strategies may vary depending on circumstances but the nature of the chemical, what protection measures are needed and how to control the substance do not change.


 * Violence
 * The column to the right of the category letter denotes whether the material has the potential to be violently or explosively reactive either with the atmosphere, water or both and is typically referred to as reactivity or 'chemical violence'. This is marked with a 'V' in the category letters row. Absence of this letter indicates that the material is not violently or explosively reactive.


 * Categories P, S, W and Y are considered violent or explosively reactive materials whilst materials in categories R, T, X and Z are not considered violent.


 * It must be noted that V is not an Emergency Action Code category itself.


 * Protection
 * The next column to the right denotes which form of personal protective equipment must be used when working in and around an incident involving hazardous materials that are depicted through the HazChem code.


 * Protection is divided into two categories:
 * LTS - use of a Liquid Tight, chemical proof Suit with breathing apparatus, and
 * BA and Fire Kit - Use of breathing apparatus with standard fire fighting kit.


 * Substance control
 * When dealing with a hazardous chemical spill, the Emergency Action Code specifies what action to take in the event of a spill, being to either dilute or contain the chemical, depending on the category. Dilute means that the chemical may be washed down the drain with large quantities of water whereas Contain requires that the spillage must not come in contact with drains or water courses and be cleaned up.


 * Evacuation
 * In the event of a chemical incident, the Emergency Action Code may specify that an evacuation is necessary as the material poses a public hazard which may extend beyond the immediate vicinity. If evacuation is not possible, advice to stay in doors and secure all points of ventilation may be necessary. This condition is denoted by an E at the end of any emergency action code. It is an optional letter, depending on the nature of the material, although emergency personnel may choose to evacuate the area despite this as a precaution.