By Special work site definition, we mean a kind of work that is performed usually for serving specific purposes emphasizing its work value, drawing its special attention, and its safety procedures. There are many kinds of special work such as:
- † Welding,
- † Cutting Metal,
- † Excavation and so on.
Welding is a means of bonding metals. A weld is created once separate items are joined in the mix and from one piece once heated to a temperature high enough to cause softening or melting. Most welding involves ferrous-based metals like steel and chrome steel. Welding covers a temperature variety of 1500℉ – 3000℉ (800℃-1635℃).
Weld joints are typically stronger than or as strong because the base metals are being joined. It is often done using different energy sources, from a gas flame or spark to an optical device or ultrasound.
Basic Types of Welding
Three basic types of welding
- Oxygen and Arc Cutting
Warning! Hazards of Welding
- General welding hazards
- ARC radiation
- Explosive dust
- Electrical shock
- Welding cleaning
- Air contamination
- Fire and explosion
- Confined space operations
- Control of hazardous energy
- Compressed gas handling and use hazards
- Others hazards related to specific processes or occupations.
In some areas, the environment can present a danger of explosion. This is true when flammable liquids, gases, fumes, or dust clouds are present. This type of area is called an explosion hazard zone or explosive atmosphere. Such zones should be marked with the appropriate warning sign.
Types of Ex-zones
Explosion hazard zones are classified depending on the frequency and duration of the potentially explosive atmosphere. This classification provides the scope of the measures to be taken to prevent an explosion. It is the employer who makes the classification.
Explosions resulting from dust occur in different ways from those involving gases, fumes, or mists so there is generally a separate classification system. The 2 main systems for classifying explosive hazard zones come from the EU and the USA but the principles behind them are the same.
The highest hazard zones reflect a situation where there is likely to be an explosion hazard most of the time. Any equipment within that zone is specially protected to ensure it will not provide a source of ignition. Suitable warning signs must indicate such zones.
The substances justifying explosion hazard zones are:
-Flammable Gases Or Fumes
-Flammable Liquids With A Flash Point Lower Than The Ambient Temperature
-Flammable Dust Clouds
When you enter an explosive zone, there are a certain number of issues that you must take into consideration. When you must perform work, you must make sure that there is written authorization for its execution.
Are there instructions present in the zone, and have you been adequately trained? Be sure to wear the recommended personal protection items and check if the equipment present corresponds to what is indicated in the work permit.
To prevent explosions in an explosion-prone environment, you can already implement several protection measures yourself. Using detection tools like an explosion meter, you can detect the presence of a gas leak.
Always use the equipment recommended in explosion-prone areas and adapt your working method accordingly. Finally, there should always be supervision of the area because any deviation from the normal values can cause an explosion.
When placing an explosion meter, you should take into account the possible source of a gas leak, the wind direction, the density of the gas, and the distance to the possible source of the gas leak. When the explosion meter gives an alarm signal, cut off all sources of ignition immediately, leave the zone and inform the person in charge.
Equipment used on site in which a risk of explosion is present must be provided with a plate indicating its suitability for use in the relevant explosion hazard zone and the certification body that has applied the standard.
It features, for instance, the symbol for explosive atmosphere, together with the classification of the equipment by group and by category as well as the type of explosive atmosphere.
Certain equipment must be specially adapted (it must bear a label or mark to indicate it can be used in an explosive area). This will guarantee that is not capable of providing a source of ignition from sparks or discharges during use. This notably includes watches with batteries, mobile phones and organizers, pocket calculators, and millimeters.
When performing excavation works, it is important to act carefully. Safety must always be your priority. There is always a risk of part excavation becoming flooded or collapsing. Suffocation and intoxication are possible.
The economic loss must also be taken into consideration: will shops in the neighborhood remain accessible by car? or are they only accessible by foot? Check also that public utility services (water, gas, electricity) will not be disturbed by your excavation works.
There can be a risk to the environment if you have to move substantial amounts of the earth as it could affect land drainage or if contaminated land has to be moved it could affect seepage into watercourses. You may have to get authorization for such operations.
When performing excavation works you must take into account very diverse types of risk. For instance, you can get electrocuted if you come into contact with power cables. If you damage a gas or oil pipeline, fire can break out, or in the worst case, there may be an explosion.
Other risks include flooding of the excavation by incoming water, soil pollution following damage to pipelines containing dangerous substances, or suffocation caused by damage to gas pipelines.
What Is Hot Work?
“Hot Work” is a kind of work that could produce a source of ignition such as a spark or open flame. Common hot work processes are welding, cutting, and brazing.
OSHA Standard 1910.252: Welding, Cutting, and Brazing (fire prevention and protection)
- Basic precautions
- Fire hazards
- Special precautions
- Combustible material
- Fire extinguishers
- Fire watch
- Prohibited areas
- In areas not authorized by management
- Relocation of combustibles
- Combustible walls
- Noncombustible walls
- Combustible cover
- Fire prevention precautions
- Welding or cutting contains
- Used containers
- Confined spaces
- Accidental contact
- Torch valve
- Protection of personal
- Welding cable
- Eye protection
- Specifications for protectors
† Fire Prevention Safeguards
† Special Precautions
Fire Prevention Safeguards
- Fire Hazards ought to be removed if the welded object can’t be readily affected.
- Guards ought to be used if removing fire hazards isn’t attainable.
- Restrictions apply (no cutting or welding allowed)
- Protect nearby combustible materials from sparks. So, fire Extinguishers should be prepared for fast use;
- Fire watch lasting at least 30min after welding or cutting operations is needed;
- An accountable individual should examine the realm and designate precautions, ideally by written permit;
- Flammable materials should be swept 35 feet away and flammable floors should be wetted or protected;
- Flammable walls should be secure or guarded;
- Fireproof walls, partitions, or ceilings (when welded);
- No welding on bound metal building elements having flammable covers or layers;
- Used containers should be cleansed of combustible materials or alternative materials that might unleash toxic combustible vapors once heated.
Protection of Personnel
- A railing or alternative appropriate fall protection should be provided as needed.
- Welding cable and other equipment must be kept clear of passageways, ladders, and stairways.
- Eye protection and protective equipment of specific appropriate types must be protected from arc welding rays.
The 35 – Foot Rule
● All combustible and flammable materials within a 35-foot radius of hot work should be removed.
● Once combustible and flammable materials within a 35-foot radius of hot work can’t be removed they must be covered with flame retardant traps and a hearth watch must be announced.
● Floors and surfaces within a 35-foot radius of the hot workspace should be swept from flammable dirt or junk.
● All gaps or cracks at intervals in the walls, floors, or ducts that are potential travel passages for sparks, heat, and flames should be covered.