Tuesday, 23 February 2010

Safety Helmets

Every year, in the workplace, particularly in the construction industry, workers are killed and many others injured as a result of head injuries. If you wear a safety helmet your chances of being seriously hurt are greatly reduced. Wearing one could save your life.


Personal Protective Equipment (PPE) is always the last line of defence. Wherever possible, other measures should first be taken to reduce or control the risk.

HSE regulations require that suitable head protection i.e. safety helmets, must be provided and worn where there is a risk of injury. If you are in control of a site you need to assess the risks of head injury. There may be risks from falling materials or from knocking into low scaffolds or items of plant. If there is risk of injury you must provide your employees with safety helmets and decide when, where, and how they should be worn. Safety helmets must always be worn in designated "hard hat" areas.

Industrial safety helmets should be designed and manufactured to European Standard BS EN 397, and carry the CE mark. They are intended primarily to provide protection to the wearer against falling objects and are not intended to provide protection against off crown impacts. The mandatory requirements for these helmets includes for them to have flame resistant properties.

In addition to the mandatory requirements the helmets may have shock absorption properties at very low temperatures and very high temperatures, have electrical insulation properties, have lateral deformation properties, and provide protection against molten metal splash.
Helmets are tested to provide a wearer protection from a force roughly equivalent to a 16 oz. hammer dropping 40 feet.

Duties of Employees and the Self-Employed

Employees must wear their safety helmets properly and follow the instructions of the rules made by their employer. They should take care of their helmets and not misuse them. Any defects or problems should be reported promptly.

In the case of self-employed contractors if safety helmets are not provided on site, they must supply their own. They must wear them where there is a risk of head injury or when told to do so by someone in control. They also need to follow the rules made by the person in control of the site, and in addition, maintain and replace the safety helmet whenever necessary.

Selection of Suitable Safety Helmets

Helmets come in a variety of designs and it is important that the right type is provided for the work to be done. A properly fitting safety helmet should have the right shell size for the wearer and an easily adjustable headband, nape and chin strap.

The range of size adjustments should be large enough to accommodate thermal liners often used in cold weather.

The harness is an integral part of all helmets and works by stretching which absorbs some of the energy of the impact. The harness also spreads the force of an impact evenly over the head minimising the risk of harm to the user.

The helmet works rather like the crumple zone on a car. The force of the impact will be largely absorbed by the helmet shell, with the harness also absorbing some of the shock by stretching. The shell or harness may well crack, this is part of the design features.

The helmets should be as comfortable as possible, this helps reduce fatigue levels and to limit the risk of people not wearing them, because they find them uncomfortable.

Comfort is improved by the following:
• A flexible headband of adequate width and contoured both vertically and horizontally to fit the forehead.
• An absorbent sweatband that is easy to clean or replace.
• Textile cradle straps.
• Chin straps (when fitted) which:
o fit around the ears;
o are fitted with smooth, quick-release buckles which don’t dig into the skin;
o are made from non-irritant materials;
o can be stowed on the helmet when not in use.

Wherever possible, the helmet should not hinder the work being done. For example, a helmet with little or no peak is useful for a surveyor taking measurements, or to allow unrestricted upward vision for a scaffold erector. In other areas there may be need of a peak and even a visor.

Chin straps should be provided and used if a job involves work in windy conditions, especially at height, or repeated bending or constantly looking upwards. Helmets should be able to be used with any other PPE, e.g. ear defenders or eye protectors, without limiting the effectiveness or comfort of any of the items. Never attempt to modify existing helmets to take these fittings as this may weaken them.


Safety helmets must be maintained in good condition the following points must be implemented:
• Be stored in a safe place, e.g. on a peg or in a cupboard on site
• Not be stored in direct sunlight or in excessively hot, humid conditions because long-term exposure can weaken the shell.
• Be checked regularly for signs of damage or deterioration.
• Have defective parts replaced (if the model allows this). Parts from one model cannot normally be interchanged with those from another.
• Have the sweatband cleaned regularly or replaced.
Before the safety helmet is issued to another person, it should be inspected to ensure it is serviceable and thoroughly cleaned in accordance with the manufacturer's instructions, e.g. using soap and water. The sweatband should always be cleaned or replaced.

Damage to the Shell

Damage to the shell of a helmet can occur when:
• Objects fall onto it.
• It strikes against a fixed object.
• It is dropped or thrown.
• Certain chemicals can weaken the plastic of the shell leading to rapid deterioration in shock absorption or penetration resistance. Chemicals which should be avoided include aggressive cleaning agents or solvent based adhesives and paints. Where names or other markings need to be applied using adhesives, advice should be sought from the helmet manufacturer.


Normally, helmets should be replaced at intervals recommended by the manufacturer. They will also need replacing when the harness is damaged or if it is likely that the shock absorption or penetration resistance has deteriorated i.e. when the shell has received a severe impact, or if deep scratches occur (i.e. to a depth greater than 25% of the shell thickness) or if the shell has any visible cracks.

Any helmet that has suffered an impact should be replaced whether damage is visible or not. The internal structure of the helmet may be damaged.

There is a lot of confusion as to what is considered to be an acceptable working life of a safety helmet. There are no hard and fast rules concerning this. There is no test in the European Standard to cover this as there are too many variables to be taken into account.

In use, head protection is generally treated with a lack of care, often being thrown or dropped, used for storing or carrying of all sorts of items, or carried on the rear window shelf of a vehicle. Any of these actions are likely to reduce performance.

It is unlikely that a helmet will be offering adequate protection five years after manufacture. With this in mind the European Standard requires the manufacturer to mark each helmet with the quarter or month and year of manufacture.

High Performance Standards

The EN 397 standard is for general use in Industry it may be that in specific tasks there is need to look at a higher standard.

High performance industrial helmets meeting the requirements of EN 14052 offer greater protection from falling objects, protection from off crown impacts and protection from penetration by a flat blade striker. The helmets also include a retention system that meets mandatory requirements for system release and system effectiveness properties. The helmets have the same flame resistant properties as the industrial safety helmets and offer the same optional protection against other risks with the exception of lateral deformation.

Helmets meeting the requirements of EN 12492 are primarily intended to protect the upper part of a wearer's head against hazards that might occur during activities carried out by people climbing. Although originally intended to protect the wearer against hazards that might occur during mountaineering activities, helmets CE marked to this standard are also being marketed for other uses, for example rescue work in hazardous environments and wild land fire-fighting, these are particularly useful for arborists.

They offer protection from falling objects, including front, rear and side impact, and offer protection from penetration. The helmets are ventilated and also include a retention system that meets mandatory requirements for system release and system effectiveness properties. These helmets have no requirements for flame resistance.

Granite Workwear offers helmets that comply to EN 397, EN 12492 and EN 14052, if you are unsure which would be suitable for you please contact us directly using the contact facility on our website.

Thursday, 11 February 2010

Eye Protection for Welding

At Granite we have recently introduced a range of welding helmets and masks from Bolle for protection of the eyes when carrying out welding of all types. We also have Welding Safety glasses suitable for people who are walking through areas where welding is being carried out and for the welders when carrying out tasks when they are not using the masks, these offer protection against flying objects, see Bolle Univis 1011 Welding Safety Glasses on our website.

Risk of Injury

While most welding-related eye injuries are reversible, more than half of injured workers return to work in less than two days and 95 percent in less than seven days, some eye injuries are irreversible and permanent visual impairment occurs. This is especially true with infrared and visible spectrum (bright light) radiation. Both can penetrate through to the retina and can cause permanent retinal damage, including cataracts, diminished visual acuity, and higher sensitivity to light and glare.

Welders are not the only workers at risk. While the welding arc is the principal source of ultraviolet radiation, other workers in the area can sustain eye damage from the radiation as far as 50 feet away with the radiation reflecting off shiny surfaces, concrete, or unpainted metals. To counteract this reflection, you should install shielding curtains where practical or require that all workers in the area wear appropriate eye protection.

Selecting the right helmet

To make the right choice in selecting a helmet, it is important to understand the meaning of arc flash and what types of emissions radiate from the welding arc. Arc flash is simply the unexpected exposure of the eyes to the welding arc. The welding arc emits several forms of light including ultraviolet, infrared radiation and high-intensity visible light. Both infrared and ultraviolet radiation can cause permanent damage to the eyes, such as retinal burns. While high-intensity visible light may not cause permanent eye damage, it may leave the operator with temporary discomfort, similar to being exposed to the flash of a camera bulb.

Many people mistakenly think that the lens shade number corresponds to the amount of protection that is provided to the eyes and hence the higher the number, the better the protection. In reality, all properly constructed quality welding lenses, have a screen that filters out 100 percent of the harmful ultraviolet (and infrared) wavelengths and provides protection to the eyes. The number just denotes the amount of darkness provided by that particular lens and should be used by operators as a guide to select the one that is most comfortable but still provides good visibility for carrying out the operation.

High quality auto-darkening helmets provide UV and IR protection even when the helmet is not activated, you are always protected. However, for maximum comfort, look for a high quality helmet that has a response darkening time of 0.4 of a millisecond or less. Less than a millisecond is not perceivable by the human eye and will provide the most comfort. The auto-darkening helmets in the Bolle range work between 0.2 and 0.25 milliseconds.

Helmets come with either battery power or solar power as is the case with the Bolle range. In most cases, it simply is a choice of personal preference and what is most convenient to the operator. With a battery powered helmet there is a chance however of being flashed. These helmets offer a feature that will automatically turn off the battery after the helmet has been sitting idle, or the batteries may have lost their charge. If the welder isn't careful, he could get arc flash thinking that his helmet is still dark. Solar powered helmets do not suffer from this and also eliminate the time and cost of recharging.

Fixed or variable shade

If you are always using the same arc welding process on the same material, a fixed shade is sufficient. But if you, like most welders, are using a variety of materials and welding a number of different applications, your best bet is a variable shade, which will adjust to the correct darkness for your particular process. As an example, when you are TIG welding at lower amperages, you may need to lighten up the lens to see what you are doing, a variable shade will allow this while a fixed shade will not.
Types of Welding

MIG is short for Metal Inert Gas welding. The system uses a metal wire fed through the gun surrounded by an inert gas such as Argon, because the cost of inert gases are high this system is not generally used for welding steel, but is more used for aluminium.

MAG is short for Metal Active Gas welding. The system here also uses a metal wire but in this case is surrounded by an active gas such as carbon dioxide. The lower cost has widened the use of this system to include steel welding.

TIG is where an arc is formed between a non-consumable tungsten electrode and the metal being welded. Gas which can be Argon, Argon and Hydrogen, or Argon and Helium, is fed through the torch to shield the electrode and the molten weld pool. If there is a need for filler wire then this is added to the pool separately.

The benefits of this type of welding are: superior quality welds, the welds can be made with or without filler metal, there is fine control of heat and there is no splatter and low distortion.

Plasma welding is very similar to TIG as the arc is formed between a pointed tungsten electrode and the work piece. However, the electrode is positioned within the body of the torch allowing the plasma arc to be separated from the shielding gas envelope. Plasma is then forced through a fine-bore copper nozzle which constricts the arc. By increasing welding current and plasma gas flow, a very powerful plasma beam is created which can achieve full penetration in a material, as in laser or electron beam welding. During welding, the hole progressively cuts through the metal with the molten weld pool flowing behind to form the weld bead under surface tension forces. This process can be used to weld thicker material (up to 10mm of stainless steel) in a single pass.