Working at Height - Are you properly protected?
Published: 10th Oct 2004
When working at a height, whether on a roof or a tall mast, protection against a fall is crucial. How can you be certain that the equipment you use as your life insurance is up to the job?
With a great variety of personal protective equipment (PPE) on the market to protect against falls from a height it is imperative that the one suited for the circumstances is chosen. Putting the wrong product on your body could lead to severe injury or even death in case of an accident. But how do you choose the right one? And how do you know that it can be trusted to save you in a real life situation?
How to choose the right type of PPE
Whilst working it is essential that you use protective equipment intended for that particular application in order to work safely. To do this, start by looking at the place where you are working. Let us look at two different examples where PPE against falls from height are used:
- A guided type fall arrester on a rigid anchorage line EN 353-1
- A guided type fall arrester on a flexible anchorage line EN 353-2
- An energy absorber EN 355
- A retractable type fall arrester EN 360
A fall without one of these energy absorbing devices would put a tremendous stress on the wearer's body and could have catastrophic consequences. Another example of wrong usage is where an energy absorbing device is used but connected to a work positioning belt or a sit harness. In case of a fall the body would then be arrested low on the body, at the hip or belly, causing the body to bend when caught which is likely to lead to severe injury or worse.
This article should not be considered a guide for choosing or using fall protection equipment but rather as a brief overview of the different types of PPE against falls from a height on the market and their different usage. Before beginning any work at height and using this kind of PPE in the field make sure that you have received proper training and instruction and know the equipment's limitations.
How is the product tested?
Let's say you have been supplied with a fall arrest system suitable for the work you are about to perform. You have also been trained on how to use the equipment. But you will be using this equipment as a lifesaver. Can you really trust this pile of rope, textile webbing and delicate looking metal connectors to do their job when needed? How is it tested? And tested by whom?
In order to be put on the market, personal protective equipment must fulfil the basic health and safety requirements in Directive 89/686/EEC. PPE is divided into three categories:
- Category I - PPE of simple design where the designer assumes the user can himself assess the level of protection provided against the minimal risks concerned the effects of which, when they are gradual, can be safely identified by the user in good time. Examples of Category I PPE are swimming goggles and gloves for gardening, cleaning or against high temperatures not exceeding 50º C
- Category II - All PPE belonging neither to category I or category III are considered category II. Examples are helmets, swimming aids and eye protectors
- Category III - PPE of complex design intended to protect from mortal danger or against dangers that may seriously and irreversibly harm the health, the immediate effects of which the designer assumes the user cannot identify in sufficient time. Belonging to Category III are protective clothing against electrical risks, temperatures above 100 º C and chemical attack. Also respiratory protective equipment and helmets for firefighters
Since a fall from a height is likely to have fatal consequences for the user, all PPE to protect against falls from a height belong to category III.
Category III products are type examined by a Notified Body that will, provided the product meets the requirements, issue an EC type-examination certificate. After the type examination a Notified Body (not necessarily the same one that issued the certificate) will carry out a quality control of the PPE. This quality control is ongoing and will be in the form of an annual re-test of the PPE or an annual (at least) control of the manufacturer's quality assurance system.
A brief overview of the certification process:
The manufacturer applies for an EC type-examination by a Notified Body and sends test samples and a technical file to that Notified Body
The Notified Body performs a type-examination, usually according to a European standard
The Notified Body examines the technical file - drawings, material specifications, markings and instructions for use
The Notified Body issues a certificate which gives the manufacturer the right to put the CE-mark on his products
Regular control of the manufacturer's production or of his quality assurance system
How is the type examination done?
Let us take an example:
A manufacturer applies for a type examination of a full body harness with a connection point for fall arrest on the back. The harness has additional, integrated elements in the form of a work positioning belt with three connection points. Also, on the chest there are two attachment points for rescue use. All in all there are six connection points for different uses: fall protection, work positioning and rescue, and all with different requirements.
The harness has to be examined as PPE for fall arrest, PPE for work positioning and as rescue equipment. To begin with it is tested as a full body harness according to EN 361:
- The harness is first examined according to the general requirements in EN 363. This standard covers the design and ergonomics concerning all PPE against falls from a height
- The specific product standard (in this case EN 361) covers the product's materials and construction. Among several requirements, the textile material in a harness or a lanyard must be made of synthetic material that is not seriously affected by dirt, moisture or UV radiation from the sun. Sewing thread must have a colour different from the webbing so that the user can easily spot a defect when inspecting the harness before use. Metal components shall not have sharp edges that could injure the user or cut into the textile parts of the product
- Static tests are performed to determine the strength of the product. The connection point on the back is tested according to EN 361. The harness is placed on a wooden dummy (a torso lacking head, arms and legs) with a steel ring in each end. The bottom ring of the dummy is attached to the testing machine while an upward force is applied to the harness' attachment point. The force is gradually increased until 15 kN is reached. This force is then held for 3 minutes during which time the harness must not separate from the dummy. The test is repeated in a downward direction by fastening the dummy's upper ring and pulling the harness' attachment point downwards with a force of 10 kN for another 3 minutes
- Dynamic testing demonstrates how the harness works when arresting a body after a fall. It can also be considered a complementary strength test in accordance with EN 361. In this test the weight of the wooden dummy should be 100 kg. A rope with a length of 2 metres is attached between the connection point on the harness and a rigid test rig. The dummy is then raised so that it will fall feet first a total of 4 m before it is arrested by the rope and harness. The test is repeated with the dummy falling head first. The same rope is used for this test and the height of fall is again 4 m. The test is considered a pass if the dummy is held by the harness and if it is arrested in a head-up position with an angle between the longitudinal axis of the dummy and the vertical not exceeding 50°
Any additional elements, in this case the work positioning belt and the rescue points, have to be examined as well. Work positioning belts are covered by EN 358 while rescue harnesses are specified in EN 1497. Rescue harnesses are not considered PPE but when integrated with a full body harness, which is PPE, these connection points will have to be looked at.
Work positioning belt (EN 358):
- The requirements for design, construction and materials are similar to those concerning the full body harness but there are requirements specific for a work positioning belt, for example minimum dimensions for the parts in contact with the body. This in order to provide sufficient support to the user
- For the static test, the belt is attached around a cylinder that is fastened in the test machine while a force of first 5 kN, then 15 kN pulls the attachment element of the belt in the opposite direction. At 5 kN, it is noted whether the belt slips through the buckle. At 15 kN, it is observed whether the belt releases from the cylinder or not. If the belt is equipped with more than one attachment element, the test is repeated for each attachment. The exception is where there are two symmetrical attachments that are similarly connected to the belt. Then only one of them has to be tested.
- A dynamic test is performed using the same wooden dummy as for the fall protection point (on the back). The height of fall is however only 1 metre for the work positioning belt as opposed to 4 m for the fall arrest point on the back.
Rescue points (EN 1497):
- Ergonomics, materials and construction requirements are similar to the other product standards
- Two dynamic tests are carried out on the attachment point. If there is more than one attachment point, the test is repeated for all of them. The drop is 1 metre and the same rope is used for both tests. At the test, the harness must hold the dummy, no body-supporting part may break or rupture and no elements of the harness shall become detached
- A static test is also performed on each attachment point. An upward test force of 15 kN is applied for a period of 3 minutes and as in the dynamic test, no body-supporting part may break or rupture and no elements of the harness should become detached
The differences in strain for the dynamic tests (4 metre drop in EN 361 and 1 metre drop in EN 358 and EN 1497) go some way to illustrate the differences in usage and above all the importance in using the connection points only for what they are intended. Utilising an attachment point designed for work positioning or rescue use for fall arrest could lead to broken equipment or worse, to the user being arrested in the wrong way with disastrous consequences. It is therefore very important that the manufacturer marks the different attachment points to avoid misuse and that they clearly state in the instructions accompanying the PPE how the attachment points should be used.
Several parts of a harness consist of metal components. As mentioned earlier, these are checked for sharp edges to avoid damage to the textile parts. They must also be corrosion resistant so they don't stop working after being exposed to the elements. Components made of stainless steel are the best from this point of view and need not be tested (with the exception of heat-forged stainless steel) due to the material's well-known characteristics. There may however be reasons (cost, weight, etc) for choosing other materials. These will then need to be tested for corrosion resistance. During the test the specimens are exposed to a salt spray for 24 hours after which time they must still be functioning normally.
Connectors that are sold as separate components (hooks, karabiners, etc) have to be tested according to EN 362. In addition to the tests mentioned above (sharp edges, corrosion test) there is also a static strength test. Further, it is verified that the connector is self-closing and either self-locking or manually locked. It must only be able to open with at least two consecutive and deliberate manual actions in order to prevent accidental opening during use. EN 362 is in the process of being revised to include further test methods and also to cover the large amount of connector variants that have emerged since the standard was written more than 10 years ago.
In case of the product failing in one or several tests, the manufacturer must improve the product in order to proceed with a re-test. On arrival at the laboratory the modified PPE is compared to the previously tested failed version to determine if a limited re-test is sufficient or if a complete type test has to be performed. Once the product has passed all the tests, the process can continue with examination of the technical file eventually leading to the issuing of a certificate. This in turn means that the manufacturer can put the CE-mark on his products and place them on the market.
SP Swedish National Testing and Research Institute
Box 857SE-501 15 Borås
Phone: +46 33-16 50 00
Fax: +46 33-13 55 02
Published: 10th Oct 2004 in Health and Safety International