Building maintenance units (BMU)
Mounted permanently at roof level, BMUs are the safest and most complete form of suspended access system, providing full lateral, horizontal and vertical movement of the working platform. BMUs provide hoisting heights of up to400m and jib outreach up to 40m, enabling safe access to even the tallest and most complex building facades.

Cradles have a typical working load of 250kg, although additional loads can be designed into the systems to facilitate glass replacement winches for future maintenance of the building. BMUs can either be in a fixed position or running on anchored or freelaid tracks. Alternatively, trackless BMUs that can run on a concrete surface with the aid of a guide rail, enabling the terrace area to be utilised for pedestrian access or other activities are available.  All BMUs are required to be CE approved and manufactured in accordance with European standard EN1808 and machinery directives incorporating fully counterweighted designs to ensure complete stability in all working load conditions. BMUs are generally manufactured from hot dipped galvanised steel and aluminium cladding, complete with a paint finish in a range of RAL colours. Ergonomically designed cradles provide a safe and comfortable work environment with lengths ranging from 2.0m to 10m.

Special BMUs
For buildings with particularly challenging façade features, like large towers, parapets or screens, a variety of bespoke functions can be incorporated to overcome the most demanding situations. Turrets can be added into the jib ends to allow the cradle to pass over high obstacles without the need for luffing or BMUs with articulating “knuckle” jibs can be supplied to allow the machine to reach around the obstruction.

Pantograph Cantilever Cradles
To enable access to façades beneath projections, such as soffits or brise soleil shading, or into recesses, BMUs can incorporate a special pantograph or cantilever unit, which enables the cradle to maintain close contact with the building façade.

Monorails
A monorail system comprises a permanently installed aluminium track complete with either single or double suspension trolleys. Standard range monorails run horizontally and can be roof, face or soffit mounted. Climbing trolleys can be used to provide access to curved, sloped or tapered façades. It can be fixed to an incline of any angle including vertically and has been designed to work in all weather conditions, even on wet or frosty tracks.

Designed to blend with the architecture, monorails are offered with either mill finish, anodised or PPC. Used in conjunction with a demountable cradle, the hoists of which enable vertical movement up and down the facade, the suspension trolley allows the cradle to traverse horizontally along the façade.  These trolleys can be either manual or motorised.

Self hoisting demountable cradles
Manufactured as either one or two person platforms, demountable cradles are required to meet the special requirements set by European Standard EN1808 for permanently installed access equipment to ensure safety, reliability and durability.  Made from lightweight, high-grade aluminium profiles with galvanised steel frames and stainless steel fasteners, cradles incorporates secondary safety devices to guard against main suspension rope failure. To guarantee functionality and dependability, the cradles control panels are clearly marked for ease of use.

The standard length of a two-person cradle unit is 2m, although special platforms for unique applications and other lengths can be provided.

Lateral restraint systems
On buildings where the drop is 40m or more in height, restraint systems must be provided to prevent any undue sway of the cradle when in use due to wind force.  

Suspension rope restraint systems comprise a series of permanently installed anchor sockets, fixed to the building's façade. The height of the building and width of the cradle determine the number and position of these sockets. The first band of restraints should be no higher than 40m above ground level, with subsequent bands no more than 20m apart.  On descent, the cradle will automatically stop at the first band of restraints, enabling the operator to connect short lanyards fixed to the suspension wires into the sockets.  The cradle can then continue safely in descent.

Travelling gantry systems
Travelling gantry systems are designed to provide safe access to flat, sloping or curved areas of glazing, such as roof lights, domes or atria.  Systems can be used for both internal and external applications and can be manually or electrically traversed. They are the ideal access solution for maintaining large areas of glazing as gantries can extend beyond 30m, incorporating free spans in excess of 20m. Travelling gantries are designed to blend with the architecture and are intended to form an aesthetic part of any rooflight or atrium.

Manufactured from either aluminium or steel, systems are offered mill finish, anodised or powder coated to a RAL colour.  To provide access to vertical areas of glazing beneath the atrium, the underside of each gantry can be equipped with either suspension points or monorails for use with our one or two person demountable cradle.

Travelling ladder and mast systems
To provide access to vertical or very steep areas of glazing, a variety of travelling ladder and mast systems are available. Manufactured from either aluminium or steel, these systems can be used for both internal and external applications and can be manually or electrically traversed along either face or roof mounted runway tracks.  Travelling ladders are a safe and cost-effective means of access to a variety of glazed areas and will be supplied with either an integrated fall protection system or a vertically moving platform for added stability.

Personal suspension systems
Sometimes it is impractical to incorporate a full permanent access system into a building design. Alternatively, existing buildings may not be able to accept the applied loads of large counterbalanced access machines. In these cases personal suspension systems may be appropriate. Personal suspension systems are a range of anchorage devices designed and installed specifically to allow access to high level façades via industrial rope access techniques.

Rope access track systems
On buildings with large expanses of façade, the installation of a track system enables operatives to traverse quickly and efficiently between work places without the need for multiple rope rig and de-rig.  Track systems consist of a unique range of aluminium extrusions that incorporate small trolley units for ease of movement along the façade. Each trolley has twin suspension points and a small parking brake, which is applied when either descending or ascending, or when the trolleys are parked in the designated rigging point.

Installation of the tracks can be either face or soffit mounted. Face mounted systems will be fixed back through the curtain walling or glazing and connected to the main structural frame via purpose engineered support jibs. Soffit-mounted systems consist of sections that can be concealed within the building effectively making them invisible when installed.

Rope access eyebolt anchors
For buildings with smaller areas of façade or for tall buildings that require infrequent rigging and de-rigging of ropes, the installation of rope access eyebolt anchors may be the perfect solution.  Available in either galvanised, polyester powder coated or stainless steel, eyebolt anchors can be roof, face or soffit mounted and can be fixed to a variety of structures, including concrete, masonry or steel work. With roof-mounted anchors an associated parapet protection system may be required to avoid damage occurring to the coping at transfer point. Face or soffit mounted anchors are applicable where operatives need to traverse short distances either horizontally or on an incline, alternatively they can be utilised as relay points beneath projections or within recesses. For ease of movement between each anchor when suspended from them, our designers pay particular attention to optimal spacing between eyebolts.

Rope access davit
On buildings with isolated strips such as stairwells or for roof-mounted applications where it is not possible to provide parapet protection, davits provide a low cost, effective and extremely discrete anchor system.  Fixed back through the roof to the main structural frame, the davit comprises a fixed base and upright socket with a rotating head. When the system is not being used the head can be rotated through 180 degrees inboard of the parapet rendering it invisible from ground level. The rotating head also provides safe and easy access for the initial rigging of ropes. 

NB - in accordance with BS EN 7985 all rope access anchorage systems are required to be designed to withstand a 15kN load.

BRACKET TO STRUCTURE CONNECTIONS

The connection back to structure is critical and bolted connections should be designed in a manner as to be structurally adequate with a factor of safety (FOS) of 3, mechanically resistant against loosening and protected against corrosion.  In order to satisfy the ‘Thorough Examination’ requirements of the Lifting Operation Lifting Equipment Regulations (LOLER) all of the anchorages must be designed to enable periodic inspection and ongoing maintenance.

BS 6037-1: 2003 emphasises the need for information exchange about the suspended access equipment (SAE) at the earliest stages of a project.  Those included in this exchange are the architect or designer, contractor, the structural engineer, planning supervisor and the equipment manufacturer.  It is essential to involve an authority that will be responsible for carrying out thorough examinations of the connections such as The Safety Assessment Federation Ltd (SAFed) members.

Initial Thorough Examination - The person carrying out the LOLER thorough examinations may want to inspect all connections to the structure including those which will be hidden.

Subsequent Examinations - From the initial thorough examination a revised scheme may be prepared to determine future frequency of examination of connections.  Connections will need to be designed to take account of all statutory regulations. Drawings showing the type of connection and method of installation should be retained together with documents that verify the integrity of the installation such as, photographs, hand over sheets, independent inspection reports.

Author - Karl Greenfield