Abschnitt 5 - 5 Fire protection and First Aid
Machines: Fire protection
Since the European Machinery Directive (2006/42/EC) came into force, the manufacturer of machinery is obliged to take into account possible fire and explosion hazards arising from his/her machine as part of his/her risk assessment (MD Annex I, 1.5.6.). The operating instructions describe protective measures against fire and explosion hazards. The clause "Intended use" specifies the suitability for processing magnesium materials.
Machines which were placed on the market before the Machinery Directive entered into force in 1995 (old machines), are considered to be work equipment within the meaning of the Betriebssicherheitsverordnung (Industrial Safety Ordinance). In this case, the user must initially check whether the machine is suitable for machining magnesium materials within the scope of the intended use, and if the necessary protective measures against fire and explosion hazards are observed.
Requirements and protective measures against fire and explosion hazards for various machines and systems are described in Clause 2.
Fire-extinguishing agents
Due to the high combustion temperatures of magnesium of up to 3,000 °C and its reactivity with water (formation of oxyhydrogen gas), only special fire-extinguishing agents are suitable. In general, most fire-extinguishing agents for extinguishing magnesium fires are classified into fire class D (metal fires).
Therefore, the following fire-extinguishing agents are suitable for extinguishing burning magnesium:
fire-extinguishing powder of fire class D
dry magnesium covering salts
dry and rustproof grey cast iron chips
dry sand or dry cement
special extinguishing agents with proven extinguishing effectiveness
Argon as a fire-extinguishing gas is only suitable for use in restricted, confined spaces (containers, technical installations), if an extinguishing concentration of the gas (< 4 % of residual oxygen content) is maintained for a sufficient period of time. An effect can only be achieved if the heavy inert gas argon forms a persistent insulating layer against the atmospheric oxygen.
Magnesium fires must not be extinguished with water or with common fire-extinguishing agents such as carbon dioxide or nitrogen, as burning magnesium reacts with them.
The following agents are not suitable for extinguishing burning magnesium:
extinguishing powder of fire classes A, B and C
water and water-containing substances
carbon dioxide
nitrogen
Instruction of employees
As part of the instruction, comprehensive information on the characteristics and hazards of magnesium and its fire behavior is absolutely essential.
This knowledge can be imparted in the course of a regularly conducted practical fire-fighting exercise. The use of the correct extinguishing agent, its storage location and the appropriate PPE and protective clothing against magnesium fires should be discussed. Under these conditions, the instructed employees can then extinguish small incipient fires on their own.
In general, the fire brigade must be informed in the event of a fire.
For useful information for instruction, see DGUV Leaflet Fachbereich AKTUELL FBHM-043 "Brand an Werkzeugmaschinen - Was ist zu beachten?" (English version: "Fire on machine tools - What has to be considered?")
Notification of the fire brigade
Before starting work with magnesium, it is essential to inform the local fire brigade or the works fire brigade. It is reasonable to include the fire brigade in the preparation of a fire protection concept as well as the selection and quantity of suitable fire-extinguishing agents. The performance of regular fire-fighting exercises also increases safety.
It is also advisable to invite the local fire brigade to the exercises in order to introduce them to the localities in the event of an emergency. A fire brigade must also know the internal locations of the fire-extinguishing agents and the individual fire compartments.
Constructural fire protection
If magnesium is machined or processed for the first time or if an existing hall is converted to magnesium machining, the existing fire protection concept must be adapted to the additional fire hazards. Additional fire protection measures may be required (see notes on construction equipment, DIN 4102, DIN EN 13501).
For example, sufficient fire-extinguishing agents of fire class D have to be provided in addition.
When converting an existing hall, it may be necessary to reconsider and modify the fire protection measures, for example a sprinkler system. The fire brigade can provide support.
First Aid
The organization of first aid in the company is one of the basic obligations of employers. First aid includes all measures that are necessary in the event of accidents, acute illness, poisoning and other emergencies until the arrival of the rescue service or a doctor. This includes, for example: securing the accident site, rescuing casualties from acute danger, initiating an emergency call, carrying out lifesaving emergency measures and caring for affected persons.
The "Small First Aid Box" according to DIN 13157 and the "Large First Aid Box" according to DIN 13169 cover the basic requirements for first aid material.
Additional materials may be required due to company-specific hazards.
Depending on the number of employees working in the company, a sufficient number of first aiders must be available. This task can be carried out by all employees. Prerequisite is the successful training in a first aid course and participation in regular refresher courses every two years (first aid training).
Working with magnesium chips involves a risk of injury from cuts, which can lead to protracted inflammations.
On the other hand, there is an increased risk of burns on contact with molten metal, crucibles and hot workpieces etc. in the casting area.
First aid measures are also described in the activity-related operating instructions, e. g. for the application areas of magnesium die casting, machining of magnesium, melting and molten metal treatment (see Annex).