This best practice guideline outlines safety net requirements and the safe use of safety nets.
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PDF Safe use of safety netsA fall from a height is likely to result in a serious injury. By installing safety nets below a high-level work area, there is less likelihood that the person will be injured if they fall.
Regardless of the time spent on a roof, the risk of falling is high. Any fall is likely to result in a serious injury. Safety nets installed below a high-level work area reduce the distance that a worker can fall. They absorb the impact of the fall and provide a &#;soft landing&#; to reduce the likelihood of a person being injured.
Safety nets are collective fall arrest systems, not fall restraint systems. That is, they provide passive protection from falls while allowing people to work at height without restricting their movement.
Collective fall arrest systems include:
This Best Practice Guideline covers the safety requirements and safe use of safety nets to protect people from being injured by a fall from a height. This information is for anyone who has to provide a safe place of work and make sure that all plant and equipment is safe. It describes best practice for:
The Health and Safety in Employment Act (HSE Act) requires that all practicable steps must be taken to prevent a person at work from being harmed. People who have responsibilities under the law include:
This means where it is possible for someone to fall from a height while working, all practicable steps must be taken to prevent them from being injured, regardless of whether they are working at height for a short or long time.
There are no New Zealand Standards for using safety nets as fall arrest systems, so this guide follows the test methods, installation procedures and safety net positioning limits described in the following British and European codes of practice and standards:
This guideline should not be interpreted as excluding from use other materials, designs, installation procedures and test methods not specifically referred to in these standards and codes of practice. However, manufacturers and suppliers must be able to show their nets meet the same or better test and performance results than the European standards.
A device or system used to connect a safety net to the structure. May include tie ropes, karabiners or other attachment devices.
A fixing on the structure that the safety net is attached to.
A rope that passes through each mesh around the net&#;s perimeter and determines the net&#;s overall dimensions.
The horizontal distance from the edge of a work platform to the outer edge of the safety net.
The calculated maximum load that an anchor point is designed to carry.
The safety net classification based on the mesh size and energy absorption capacity.
The distance below the net that must be kept clear of objects that a falling person might otherwise strike as the safety net deflects under their impact.
A person who has acquired through a combination of training and qualifications or experience, the knowledge and skills to correctly perform the required task.
The rope that joins two safety nets together.
A rigging technique to prevent waisting at the unsupported perimeter of a safety net.
The vertical distance between a work platform and the safety net.
The amount of sag due to the net&#;s self-weight.
A series of ropes arranged in either a square or diamond pattern to form a net.
The rope used to make the net&#;s meshes.
The distance from centre to centre of the mesh.
The safety net, tie ropes or other anchorage devices, and the supporting structure linked together to provide a collective fall arrest system.
A person who or that engages any person (otherwise than as an employee) to do any work for gain or reward.
The combination of mesh, border ropes, test meshes and labels of the net.
The structure to which the safety net is attached.
A separate piece of mesh attached to a net, made from the same material and produced in the same batch as the net to which it is attached, that can be removed for testing the net&#;s UV deterioration.
A rope used to secure the border rope to an anchor point on the structure.
The effect of a net being pulled horizontally away from the structure or intended perimeter of the net, either due to over-tensioning or the net&#;s self-weight at an unsupported edge.
&#;Shall&#; or &#;must&#; are used where the statement is a legal requirement, or where a practice is the minimum threshold for safety.
&#;Should&#; and &#;may&#; are used when you should adopt the recommendation where practicable. This will help you comply with the HSE Act&#;s requirement to &#;take all practicable steps&#;.
Safety nets are designed to progressively deflect (stretch) and absorb the energy of a fall, so a falling person is less likely to be injured. The greater the fall height, the greater the impact; so the net&#;s deflection must also be greater.
Safety nets are designed to progressively deflect (stretch) and absorb the energy of a fall, so a falling person is less likely to be injured. The greater the fall height, the greater the impact; so the net&#;s deflection must also be greater. The safety net must be able to deform or deflect enough to absorb all of the energy from the fall&#;s impact up to the maximum fall height for the design.
There must be enough clear distance below the net so that the person falling does not hit an obstacle or the ground while the net is deflecting.
This guideline is for &#;System S&#; safety nets, which are horizontally-installed safety nets with a continuous border rope.
Safety nets may be either knotted or knotless with a square (Q) or diamond (D) mesh arrangement.
Notes:
WorkSafe recommends the use of knotless, square mesh for &#;S&#; safety nets.
BS EN -1 lists four classes of nets:
(1) Glasgow Caledonian University. Research Report 302: A technical guide to the selection and use of fall prevention and arrest equipment. . 7.0 Fall arrest netting (safety nets), p111.
Table 1 sets out the net classifications.
Mesh size (mm)
A1 2.3 60 A2 2.3 100 B1 4.4 60 B2 4.4 100Table 1: Classification of nets according to energy absorption capacity and mesh size.
Both classes A1 and A2 nets are suitable for system S safety nets. Class A2 nets (2.3 kJ energy absorption capacity and 100 mm mesh size) are most commonly used as the larger mesh size is lighter and has less initial sag.
Mesh rope should be made from at least three separate strands, braided so they cannot unravel. It should be tested according to BS EN -1, clause 7.3.
A border rope is a continuous rope passing through each mesh around the perimeter of S safety nets. It should have a minimum tensile strength of 30kN, and be tested according to BS EN -1, clause 7.5.
Tie ropes fasten the safety net to the structural elements and/or the anchor points on the structure being netted. They should have a minimum tensile strength of 30kN and be tested according to BS EN -1, clause 7.5.
Coupling ropes join safety nets together when more than one net is needed to protect an area. They should have a minimum tensile strength of 7.5kN and tested according to BS EN -1, clause 7.5.
All safety nets should have a label showing the:
The label must be permanently attached to the net and be legible throughout the net&#;s life.
Tests for UV deterioration of safety nets must be done at least every 12 months. All safety nets should have at least three test meshes loosely woven into the net so they can be removed one at a time for testing (see section 6 Inspections, testing, maintenance and repairs).
Each test mesh must have the same ID number, be made from the same material, and produced in the same batch as the net to which it is attached.
Notes:
BS EN -2 only applies to safety nets over 35 m2 and where the shortest side is at least 5.0 metres.
If the fall height is over 2.0 metres, the safety net must:
If a load falls onto a net less than 35 m2, the small net area means there will be less deflection and more limited energy absorption compared to nets with a larger area.
System S safety nets that are less than 35 m2 are not covered by BS EN -2.
WorkSafe recommends that when a net area is less than 35 m2, you should use a class B safety net with 4.4 kJ energy absorption capacity.
The fall height is the distance a person will fall from the work platform onto the safety net &#; see Figure 2. A greater fall height results in a greater fall impact.
Keep the fall height as low as possible by installing safety nets as close as practicably possible below the work platform. Where possible, install nets no more than 2.0 metres below the work platform. Note that BS EN -2 allows a maximum fall height of 6.0 metres (this gives a nominal fall height of 7.0 metres from a person&#;s centre of gravity) but this applies only to nets that are more than 35 m2 (see section 2.10 Size of safety nets).
Within 2.0 metres of the net&#;s outer edges, the fall height between the work platform and net should be no more than 3.0 metres. This is because safety nets cannot deflect as much at corners and edges (BS EN -2). See Figure 3.
There must be enough clearance below the safety net to allow for it to deform when a person falls onto it. The amount it will deform depends on the height of the fall and the span of the net. See figure 4.
The graph in Figure 5 (from BS EN -2: Figure 4) shows typical deformation when an object lands on the net. It is based on fall height and can be used to calculate the minimum clearance distance needed below the net, but only applies where the:
As an additional safety factor BS : recommends allowing an extra 0.5 metre clearance below the net.
Net sag, or initial sag, is the amount of deformation from the net&#;s own weight. Net sag should be between 5% and 10% of the net&#;s shortest side.
To have enough initial sag, the safety net should be at least 10% larger (along both sides) than the area it is going to cover. Excess netting should be under-rolled into the tie rope or attachment system (see section 4.7 Under-rolling) to spread the load evenly and avoid too much stress on individual meshes.
Safety nets should not be over-tensioned as they must be able to deflect and absorb energy from the impact of a fall. An overtensioned net, or a net with too many fixing points, may not be able to deflect enough. In either case, the impact on the person falling onto the net increases, as well as increasing the load imposed on the net and structure.
An under-tensioned net may deflect too much and if there isn&#;t enough clearance below the net, a falling person may hit an obstacle or the ground.
If a person trips when they are moving forward, they fall forward as well as downward. The distance they fall forward is affected by the height of the fall; that is, the higher the fall, the further the forward movement.
Nets providing protection at the edge of a work platform must be wide enough to include the falling person&#;s forward movement &#; see Figure 7. The width of the net between the edge of the work platform and the outer edge of the safety net is called the catching width.
BS EN -2: Table 2 sets out minimum catching widths for maximum fall heights &#; see Table 2 of this guide. As an added safety factor, BS recommends extending the net at least 1.5 metres beyond the distances given in Table 2 of BS EN -2.
Minimum catching width b as per BS EN -2: Table 2 (metres)
Table 2: Catching widths for maximum fall heights (from BS EN :2, Table 2 and Clause 4.3).
If the slope of the working platform is more than 20°:
Safety net installation must be planned and include everyone who is involved in supplying, installing and using nets.
Plan the installation before installing a safety net. You should consider:
Planning should include everyone involved in supplying, installing and using nets, including:
The designer&#;s role includes:
The installer rigs (installs) and strikes (dismantles) the nets. Before starting installation, the installer should give the main contractor or site supervisor information about:
They should also:
Once the nets have been installed, the installer should give handover documentation to the main contractor/site supervisor. The documents should verify the safety net system is fit for purpose, as well as giving written instructions on:
The installer should also give verbal instructions on all procedures.
Everyone who may be involved in a rescue must have rescue training.
(See also section 4.11 Handover documentation).
The main contractor or site supervisor is
responsible for:
The main contractor or site supervisor must also make sure:
Safety net suppliers or manufacturers must provide an instruction manual on how to safely install and use the nets.
A hierarchy of safety net installation minimises risk to the riggers. The hierarchy goes from low to high risk as follows:
Before installation, safety nets must be inspected for damage or defects. Do not use nets that are damaged or have defects.
Safety nets must have the manufacturer&#;s and removable test mesh labels. Do not use nets that do not have labels attached.
Before installing the nets, the installer should:
If the installer finds any damage or defects, the net should not be used. If the damage is reparable, the net may be repaired; otherwise it must be withdrawn from service.
If a label is not attached, or the label&#;s information is not legible, do not use the net.
Ceiling battens must not be installed until the safety nets have been removed. If they are installed before or with safety nets in place, the battens will be the first obstacle the falling person hits.
Before installing nets near live wires or overhead power cables, contact the line owner to make the wires or cabling safe.
Nets must be easily accessible to carry out a rescue or clear debris.
Dishun supply professional and honest service.
Provide access by:
People should be able to remove debris from the nets without walking on them. Do not use safety nets to collect debris, for storage, as a work platform, or for providing access to a work platform.
Safety nets are attached with tie ropes or karabiners to the supporting structure or to specifically-designed anchor points on the structure.
Based on a maximum fall height of 6 metres and an assumed load angle of 45° to the horizontal, each anchor point should have a 6 kN minimum load-carrying capacity&#; see Figure 10. The combined load-carrying capacity of the supporting structure applied over three adjacent anchor points should be at least 4 kN, 6 kN, 4 kN.
The maximum distance between anchor points according to BS EN -2 is 2.5 metres but WorkSafe NZ recommends installing anchor points at between 1.5 and 2.0 metre centres.
Safety nets used in residential, timber frame construction may need to be attached at closer centres. Anchor points and the supporting structure that the safety nets are fastened to must not have sharp edges that could rub on the tie ropes.
Safety nets may be attached directly to hot-rolled, structural steel members such as trusses, rafters, portal frames and purlin support cleats. Do not attach safety nets to gutter supports, pipework or electrical service installations.
Cold-formed sections such as purlins, ceiling battens and scaffolding tubes should not be used unless calculations show they are strong enough for the load.
Safety nets may be attached to timber structures such as rafters and top plates. Do not attach safety nets to timber purlins or ceiling battens.
Safety nets should be at least 10% larger (along both sides) than the area requiring protection (see section 2.15 Over-tensioning and under-tensioning). Reduce the net size to fit by under-rolling. This is a preferred method of reducing the net size as it distributes the load on the net evenly and gives a strong edge for the tie rope or other attachment system.
In some situations, such as when the netting must be installed from a ladder, under-rolling the net on a ladder may put the installer at more risk than gathering, so gathering may be a better option.
Where anchor points are widely spaced (see section 4.4 Anchor points), the safety net&#;s edge may pull in or &#;waist&#;, leaving a gap that a person could fall through. If waisting occurs, make an &#;eaves bag&#; by folding approximately
2.0 metres of net back on itself and stitching the sides together to create a bag around 1.0 metre deep. See Figure 12.
There should be no gaps between the safety net and the adjacent structure. If unavoidable, gaps of up to 100mm are allowed. If there are obstructions (for example, around columns), a gap of no more than 225 mm is allowed but it must not be able to get any larger.
If more than one net is needed to protect an area, join nets by:
Safety nets can be laced together using a coupling rope with a minimum 7.5 kN breaking strain (type O or greater as defined in BS EN -1). The coupling rope must pass through every second mesh and around both border ropes. Tie the ends off at the corners. The completed lacing should give a join with gaps no more than 100mm.
If joining nets by overlapping, the overlap must be at least 2.0 metres (or 20 meshes) wide, measured at the narrowest point for the entire length of the overlap. Nets that follow the slope of the roof should be installed with the upper net overlapping the lower net (referred to as &#;tiling&#;) so that if a person falls, they will not roll down the pitch and off the open end.
Once installed, the installer must inspect the safety net to make sure it is correctly installed and fit for purpose. They must then give handover documentation to the main contractor or site supervisor that includes:
The main contractor or site supervisor must keep the documentation on site for the duration of the construction project.
The safety net system should have a label with the:
If there is no handover documentation, you should regard the nets as unsuitable for use. Do not carry out work above the nets until the installer provides documentation.
Dismantling (striking) safety nets is the reverse process to installation. Safety nets should onlybe dismantled by trained installers who can identify and mark net damage.
Plan the dismantling process during the net installation planning stage, to recover the nets safely and intact. Do not drop nets to the ground in an uncontrolled way during dismantling, as damaged nets may not be able to be re-used.
A rescue plan must be in place before any work above the nets begins. Equipment needed for the rescue must be available at all times.
Rescue operations will vary depending on the site, location of the fall and extent of the injuries to the person who has fallen.
The main contractor or site supervisor is responsible for making sure that:
If possible, carry out a practice rescue before starting work above the safety net.
Visual inspections must be carried out regularly. If a net does not pass a visual inspection, do not use it.
Visual inspections of the safety nets must be carried out regularly by a competent person (see section 1.4 Definitions). An inspection regime is given in Table 3. Records of all inspections must be kept on site.
Carry out visual inspections...By the... when the net is installed installer daily before use user weekly site supervisor after adverse weather site supervisorTable 3: Frequency of net inspections.
Visual inspections include checking for:
If a net does not pass the visual inspection, do not use it. Either remove and repair it, or take it out of service permanently.
Minimum ongoing net inspection requirements are described in BS EN -1: Annex B.
General testing includes:
Test methods and requirements are described in BS EN -1: clause 7.
Test safety nets at least every 12 months to determine the amount of UV deterioration and to make sure the manufacturer&#;s minimum energy absorption capacity will be maintained for the next 12 months.
Test meshes (see section 2.9 Removable test mesh) are attached to the safety net and removed one at a time for annual testing. Test meshes must remain attached to the net until needed for testing. Do not use test meshes for any other purpose.
Nets more than 12 months old must have a current test tag or label attached to the net to confirm the net met the manufacturer&#;s energy absorption capacity requirements at the most recent testing. Keep the corresponding certificate with details on site. The test tag and certificate must not expire while the net is in use.
Test methods for UV deterioration are described in BS EN -1: clause 7.7.
Safety nets catch a falling person, but they will also catch falling debris. Debris can damage the net, and if left in the net is a hazard because it might:
When debris falls onto a safety net, immediately stop work above and below the net. Remove the debris, and have the net checked for damage by a competent person before work continues.
WorkSafe recommends one person on site is responsible for keeping safety nets free of debris.
Note: Snow on the safety net can overload the net and cause excessive deflection.
Do not damage nets during handling and storage. Damage may occur from:
When handling nets during rigging or striking:
When installing nets, do not:
Do not use damaged nets (see section 6.1 Inspections).
Following impact from a heavy object (such as a person or debris), the safety net should be checked by a competent person and if necessary, repaired or taken out of service.
Safety nets must be repaired by a competent person (i.e. someone who has completed a recognised3 training course within the past 5 years). Nets should preferably be repaired in a controlled environment, away from the site.
Repairs must be made using new material that is similar to the net mesh cord and recommended for use by the manufacturer. Cable ties must not be used as a net repair, although they may be used to hold a patch in place before stitching or to tie up the loose ends of a patch.
A label showing the repairer and date of repair must be fixed to the net next to the manufacturer&#;s label. The repairs must also be recorded and another handover certificate (see section 4.11 Handover documentation), confirming that the safety net remains fit for purpose, should be given to the main contractor or site supervisor.
Border rope repairs must be made using rope with at least 30kN tensile strength. Repairs may be spliced or machine sewn but must not be knotted. Repairs to the net selvedge should maintain the original strength of the net.
Damaged tie ropes should not be used.
C-Ring and other proprietary repair systems may only be used on safety net systems if they have been approved by the manufacturer as suitable for that net.
(3) A recognised training course is a FASET Net Repair Training Certificate
When multiple meshes of a knotless net are damaged, the net should be repaired using new patch material that has been approved by the manufacturer as being suitable for their net, and which complies with BS EN -1. The repair should overlap the entire area that is damaged by at least one mesh.
A patch may be laced to the safety net using lacing repair twine to attach all meshes (both the inside and perimeter meshes). Alternatively cable ties may be used to attach the inside meshes of the patch but perimeter meshes must be laced using repair twine.
Single mesh repairs should extend at least one square past the damage, and the repair twine must cross the damaged hole twice. Repairs should not overlap.
Repair twine should be at least 3mm thick and double knotted on either side of each node.
A knotted safety net should be repaired using new repair twine of the same type and thickness as the original net and has been approved by the manufacturer as being suitable for their net.
Cable ties must not be used to connect the repair twine. Knotted nets should not be repaired using a knotless patch repair.
The repairer must be competent in the repair of knotted nets. This is usually carried out by the manufacturer.
Store safety nets:
If a safety net has been stored for more than 12 months, it must be inspected and tested for UV deterioration before being re-used.
FASET (Fall Arrest Safety Equipment Training) have technical bulletins that address technical and safety matters surrounding the safe use of nets. See www.faset.org.uk(external link).
Checklist for safety net inspections
Y/N
Are the nets correctly labelled? Are the labels current (i.e. less than 12 months old)? Are there distortions in the line or appearance of the nets orIf any of the checks have a &#;yes&#; response, nets should either be removed and repaired, or taken out of service permanently.
Personal Fall Arrest Systems (commonly referred to as PFAS) are used frequently in the construction industry across a wide variety of trades. The components of a PFAS include an anchor, connectors, and a full-body harness, and may include a shock-absorbing lanyard, a retractable lifeline, and/or a deceleration device.
While OSHA holds employers legally responsible for the safety of their employees, it is important for every single construction worker to be an advocate for their own safety. Making sure you are properly and well informed on all things related to PFAS is one way to ensure that.
This article answers common questions surrounding one of the PFSA components: the full body harness.
There is sometimes confusion around this topic because there are different standards for the general industry vs. the construction industry. Standard .501 of the Occupational Safety and Health Administration regulations covers fall protection, specifically in the construction industry. It states:
&#;Each employee on a walking/working surface (horizontal and vertical surface) with an unprotected side or edge which is 6 feet (1.8 m) or more above a lower level shall be protected from falling by the use of guardrail systems, safety net systems, or personal fall arrest systems.&#;
It can also apply at heights lower than 6 feet if the employee is working near or above dangerous equipment or substances. To determine which situations are applicable to your trade specifically, you should read the regulation in full.
If the conditions of Standard .501 (outlined above) are applicable, then Standard .502 states that the employer is the one responsible for providing proper means of fall protection, which may include a full body harness, lifeline, lanyard and anchor.
There has been some confusion regarding whether the term &#;provide&#; when it comes to all personal protective equipment includes paying for said equipment. With a few exceptions, OSHA requires employers to provide and pay for PPE when it is used to comply with OSHA standards.
Harnesses are available for sale at local distribution centers near you. Since roofing is one of the top trades to use them, your best selection may be through a roofing supply center, even if you aren&#;t a roofing contractor.
If you have more than a handful of employees to purchase for, you may wish to consider reaching out to the distribution&#;s sales team, as they can likely offer you a discount on bulk purchases. A sales representative can also assist you in selecting the proper fit and size for your employees.
There are many different manufacturers of harnesses, each of whom believe theirs to be the best. With the lives of your employees at stake, making a safety harness purchase is not the time to skimp on quality. We recommend selecting a harness from one of the top brands, including:
Once you have purchased a safety harness, the next step is to ensure it is the proper fit for your employee and that they know how to put it on properly.
Although adjustable, some models come in different sizes, and some are even gender specific. Begin by checking the manufacturer&#;s specifications to ensure the height and weight of the employee are within the allowable limits.
1. Inspect
Safety harness components include shoulder straps and leg straps, a sub-pelvic assembly, adjustable buckles or fasteners, and one or more D-rings to connect to a lanyard. Inspect each component to ensure it is in safe working condition (more details below).
2. Position the D Ring
The dorsal D-ring is positioned between the worker&#;s shoulder blades with a fall arrest system. D-rings in other positions are sometimes included for use with ladder safety devices. For this reason, some harnesses come with D-rings on the front, sides, and lower back.
3. Buckle up legs
Your fingers should fit snugly between the strap and your leg. You should not have to force your fingers to fit beneath the leg straps.
4. Buckle up chest
A snug strap should not allow any slack. It lies in a relatively straight line without sagging.
5. Adjust
A safe and effective harness is adjusted so that all straps are snug. Make sure the D-ring stays in place once the adjustment is complete.
With the nature of the construction industry often being muddy, it&#;s very likely that a harness will need to be cleaned at some point. Here is how to accomplish that:
Storage areas for a full body harness should be clean, dry, and free of exposure to fumes, heat, direct ultraviolet light, sunlight, and corrosive elements.
Do not store harnesses next to batteries; chemical attacks can occur if the battery leaks.
Harnesses will be marked by the manufacturer with information specific to it, such as warnings, serial/model number, capacity, and the materials used to make it.
Information such as proper use, maintenance, and inspections is typically provided in a manual written by the manufacturer.
What isn&#;t included is an expiration date. That is because the only people who can determine whether a harness is fit to wear or not is you or your supervisor, by conducting a thorough inspection.
OSHA does not stipulate a mandated expiry because it could lead to a false sense of security. For example, you may question the condition of your harness but upon reading the expiration date, you confirm it is good for another year; however, it is possible the harness is not safe to wear any longer.
A harness should be considered expired and removed from service when it fails a routine inspection, no matter how old it is. If a harness is involved in a fall arrest, it also needs to be removed from service until a competent person can inspect it. Even then, the safest choice is to destroy it.
OSHA stipulates a personal fall protection system must be completed before initial use during each work shift. It does not say who specifically should conduct the inspection.
Industry best practice is to have the user conduct this &#;informal&#; pre shift inspection and to have a competent person conduct a monthly formal inspection of all equipment.
You are the top person in charge of your own safety. Supervisors and employers also have responsibilities, but it is the choices you make that have the most impact on whether you make it home safe and sound at the end of the day.
A simple visual inspection, combined with the touch and feel of the components of your harness before putting it on, could be the difference between life and death. If anything arises as a red flag or you are even remotely unsure about something, bring it up to your supervisor.
If your supervisor does not provide you with the information you require to feel safe and comfortable, you have the right to refuse to work in dangerous conditions.
Additionally, on a monthly basis, every employer should conduct an inspection of all fall protection equipment, tracking the serial number on each piece and recording the results. Any pieces that fail any inspection, pre-shift or monthly, should be removed from service immediately.
If you want to learn more, please visit our website Construction Safety Netting.