Roof anchoring
Roof anchoring devices are intended to create safety places to fasten personal protective equipment (PPE) against falling from height to a fixed structure. They are the only available solution to secure roof users working at height in places, where it is not still possible to use collective protection equipment (CPE) such as railings or safety nets. Choosing the appropriate type of anchor device depends on the fall hazard to prevent and how can we fix the fall arrest device to the structure of the building.
In this short guide, we would like to provide with a detailed analysis of available roof anchoring to protect operators working at height:
- – Roof anchoring as personal protective equipment (PPE)
- – Legal basis – European standard EN ISO 795
- Class A1 – Structural anchor points
- Class A2 – Anchor points
- Class B – Portable anchor devices
- Class C – Flexible horizontal lifelines
- Class D – Rigid horizontal anchor line – rail systems
- Class E – Deadweight anchor for flat roofs
Roof anchoring as personal protective equipment (PPE)
We should always remember that Council Directive 89/391/EEC, defining preventive action principles, prioritizes collective protection equipment (CPE) over personal protective equipment (PPE) such as EN ISO 795 anchorage devices. Legal provisions clearly state that lifelines, anchor points as well as other roof anchoring devices certified according to EN ISO 795 standard, should only be used when it is not possible to install collective protection equipment (CPE).
Collective protective equipment (CPE) is always the most effective way to prevent fall arrest. As a passive safety system, CPE allow to protect fall hazard without requiring any intervention of roof users. This is a key factor as it exclude employee’s decision to fasten themselves or not. Safety on the roof is thus always guarantee, regardless of the employee’s approach to safety procedures.
Legal basis – European standard EN ISO 795
European standard EN ISO 795 defines test methods and requirements that roof anchoring devices must meet. In addition, the above standard introduces a classification in six different classes for roof anchoring devices. Safety systems in the scope of this standard covered fall arrest devices, work positioning and restraint roof anchoring preventing from fall hazard. Depending on the location and the kind of works at height provided, we will select the proper roof anchoring device.
Considering the above, according to the fall hazard to prevent, EN ISO 795 standard mentioned the following classes of roof anchoring devices:
A1 CLASS STRUCTURAL ANCHOR POINTS
Roof anchoring device with one or more stationary anchor points, while in use, requiring permanently fixing to a structural element. This kind of anchor devices can be installed at any angle depending only of the loading direction. They are also known as “structural anchor points”. As installed, A1 class roof anchoring devices should guarantee a minimum pull-out strength of 10 KN in the loading direction. That is, in the direction that the anchor point should prevent a fall.
They can be used in most situations where it is necessary to protect against falling from height. We must take into account that this type of anchoring significantly limits the user’s mobility.
More information on class A1 roof anchoring devices right here.
A2 CLASS ROOF ANCHORING DEVICES
This kind of roof anchoring devices meet the same requirements as A1 class structural anchor points. For example, they should guarantee a minimum pull-out strength of 10 KN in the loading direction. That is, the direction that the anchor point should prevent a fall. The way those particular roof anchoring devices are designed, allow them to be used on sloping roofs. That is the key differential factor among these two anchor devices.
B CLASS PORTABLE ROOF ANCHORING
They are known as “portable or temporary” anchor devices as they can be removed without damaging the structure or the anchor device itself. So, they are not permanently fixed to the structure as in the case of A1 class roof anchoring. B class anchor devices can be reused. They represent a very interesting solution for temporary securing operators working at height. They can be quickly mounted and removed to the next area to protect.
As A class permanent roof anchoring devices, they must also withstand a minimum pull-out strength of 10KN in the loading direction. This resistance should be checked in special laboratories or by making the appropriate engineering calculations. Class B anchor points are considered PPE and covered by Council Directive 89/686/EEC (The Personal Protective Equipment Directive). For this reason, those kind of devices required CE marking.
C CLASS FLEXIBLE HORIZONTAL ANCHOR LINES
C class represents a roof anchoring device employing a flexible horizontal line for a mobile anchor point, which is intended to travel along an anchor line. Roof user is fasten properly to the mobile anchor point allowing him to move safely along the path of the horizontal line. Those devices are known as “horizontal anchor lines” or “lifelines”. This type of fall arrest systems should be installed on building roofs only when it is not possible to install collective protection equipment (CPE), such as safety railings.
C class roof anchoring device consists of:
- steel or webbing ropes,
- intermediate and extremity anchor points,
- energy absorber (reduce the energy generated in the anchor line in the event of arresting a fall),
- tensioner,
- PPE connectors which are directly fasten to the rope or through a specially adapted slider (trolley) in accordance with EN 362.
C class lifelines requirements are as follows:
- flexible anchor line should deviates from the horizontal by not more than 15° (when measured between the extremity and intermediate anchors at any point along its length)
- in the event of arresting a fall, all parts and components of the lifeline must withstand a fall factor at least twice as high (fall factor = 2)
- always remember to maintain enough clearance distance below lifeline, taking into account the full extension of the energy absorbing lanyard in the event of arresting a fall (clearance distance below anchor device).
- roof anchoring user should be fastened all the time, during the working at height, even when changing from one lifeline section to another.
Please note that C class anchor device installation must be performed by an authorized by the manufacturer installer. After “lifeline” assembly, the authorized installer should certify the compliance with the EN ISO 795 class C standard of the entire roof anchoring device by creating an acceptance report. Be careful not to mix original manufacturer’s components with counterfeiting. Unfortunately, this is an increasingly emerging fraud that causes the loss of EN ISO 795 certification for the entire installation.
D CLASS ANCHOR DEVICES
Roof anchoring device equipped with a rigid horizontal line made of steel or aluminium. A mobile anchor point (slider) is intended to travel along the anchor line. The slider (trolley) works as a connector to the PPE roof user’s. Thins kind of roofing anchor devices are known as horizontal anchor rails.
Operation principle of device: the mobile anchor point (slider) travels along the rigid horizontal line as the roof user is fastened properly all the way on to the slider.
Each of the safety rails must be fixed to the ground with structural anchor points. The strength of them must not be less than 10 KN in the loading direction (the direction that the anchor device should prevent a fall). In addition, each of the rails must have appropriate blocking endings that preventing the slider to slip out unintentionally.
The installation of this roof anchoring device is similar to class C devices, however, they are mainly used when we want to fix the safety system above the working level. For example, in order to secure wagons maintenance works, tankers unloading, airplanes inspection, etc.).
E CLASS ROOF ANCHORING DEVICES
Deadweight anchor devices are intended for flat roofs. Its purpose is to provide an anchor point in a place where, for some reason, it is not possible to install roof anchoring devices from any of the above classes. For example, there is no possibility to drill the roof. Operation principle of the device: the performance relies solely on mass and friction between itself and the surface. These types of anchor points are known as freestanding counterweight anchors.
E class roof anchoring devices requirements are as follows:
- distance from the deadweight anchor device to the roof edge (danger area) must be at least 2.5 m
- the roof slope on which the roof anchoring device is placed must not exceed 5 degrees
- the anchor device must not be used in the event of icing or risk of icing
Class E deadweight anchor device are considered PPE by Council Directive 89/686/EEC (The Personal Protective Equipment Directive). For this reason, those kind of devices required CE marking.
More information about Class E counterweight anchor devices right here.
Final conclusions
Legal provisions clearly state that roof anchoring devices should only be installed when it is not possible to use collective protection equipment (CPE). Anchor points are an ideal solution for protecting fall hazards in places, where it is not still possible to use collective protection equipment (CPE) such as railings or safety nets. The EN ISO 795 standard introduces a classification in six different classes for roof anchoring devices. Depending on the place and fall hazard to prevent, we should select the appropriate anchor devices according to the EN ISO 795 standard.
