GB2568451A

GB2568451A - Walkway system

Info

Publication number: GB2568451A
Application number: GB1713508.8A
Authority: GB
Inventors: Nicholls Richard
Original assignee: Nicholls Ind Building Services Ltd
Current assignee: NICHOLLS INDUSTRIAL BUILDING SERVICES LTD
Priority date: 2017-08-23
Filing date: 2017-08-23
Publication date: 2019-05-22
Anticipated expiration: 2037-08-23
Also published as: GB201713508D0; GB2568451B

Abstract

A walkway system suitable for access over composite insulated independently supported ceiling panels as used in cold stores. The walkway system comprises a grating on a rigid ladder frame 2, 4, 5, 6 and a wire rope system and or a plurality of lengths of studding to connect the walkway system to a supporting structure above the walkway. The frame may be made from galvanised steel or stainless steel, and the grating may be formed from glass reinforced plastic.

Description

My walk way system is specific to the construction of insulated envelopes; there is no design for the safe access over a composite insulated independently supported ceiling 5 panel system (i.e. cold store) within the industry.

Technical Information io · Deterioration and failure of cold/frozen food store ceilings (Insulated Envelopes)

Ceiling panels generally have an imposed loading of 0.25 kN/m², this equates to a limited access for one man and small bag of tools and to achieve this loading is manufacturer’s installation and maintenance of the panels must remain strictly as the original test conditions from which the loadings were determined. The loadings are based on complete panels without openings, penetrations or any other imposed loadings what so ever.

Penetrations can considerably weaken the panel and in extreme cases, cause its failure

Delamination

Panels may also be weakened and in extreme cases, collapse due to deterioration over time. Delamination refers to the separation of the outer steel faces from the core 25 material, should separation occur, the result is not a small percentage reduction in strength, instead a complete loss of integrity and strength, it has been identified, most commonly, within mineral wool (Rockwool Panels), applying additional supports to reduce the span of delaminated panels may still collapse due to the breakdown in composite action.

Walk on ceilings will deteriorate through progressive degradation under repeated heel impacts as people walk over the surfaces.

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Under test conditions it has been established that mineral core panels were up to five times less resistant than other core materials too foot traffic.

Panels are deemed fragile when they are unable to support the weight of a person and 5 the tools they are carrying. The following may cause the panels to be termed fragile:

a. Deterioration over time, such as delamination.

b. Inadequate support around groups of small and large openings or a grid of io penetrations.

c. Water ingress, especially associated to mineral wool panels.

d. A correctly installed panel system with openings/additional supports but is containing fragile lights/units.

Accessing across the surface of an independently supported ceiling system has been highlighted as a fragile surface due to them collapsing, Where frequent access is required independently supported walkways should be installed, or boards used to 20 spread loading for foot traffic and prolonged work activities.

The industry currently recommends the placement of 12mm ply wood to assist spreading weight loads during occasional maintenance engineer’s access, recent surveys have identified fixings through the ply wood walkways into the outer panel 25 skin, the fixings will contribute to weakening and delaminating the panels construction, Fire officers are concerned with the use of plywood walk ways due to them being a source of ignition.

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The system comprises of a fabricated, welded 2mm thick galvanised steel or stainless 5 steel rigid ladder frame (2/4/5/6) Figure 1, 2 & 3.

The system is available in the following 4 types of module

Right hand corner section (Figure 4.) io Left hand corner section (Figure 4.)

2440 long (Figure 5.)

1220 long (Figure 6.)

The ladder frame is lined with anti-slip 12mm thick grp yellow grating (1) to act as is the demarcated walk way, the GRP will span from one module to the next.

A 25mm x 25mm internal retaining angle (3) and 7mm set screws @ 300mm centres will lock together the components both sides of the ladder frame to comprise a rigid frame structure.

The system can either be loosely laid over the panel surface or supported from above (connecting back to the existing main portal) utilising a wire rope system and/or ml2 studding @ a minimum 1500mm centres, either side of the modules as denoted FIGURE 2.

The supported system can be supported by introducing 41mm x 41mm Unistrut (8) Figure 2. The Unistrut’s will span under the width of the ladder frame 2/5/6.

M12 studding will be fixed to the Unistrut both sides and adjusted to create a level 30 walking platform (Figure 2).

All modules will be a standard 610mm wide (Figure 1,2,3,4,5 & 6).

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The modules fixings and connections are uniform throughout regardless of shape or length (Figure 3).

1. The walkway system is designed and fabricated to suit the client’s requirements to achieve a designated safe walk way for maintenance engineers.

2. At present panel manufacturers recommend the use of 12mm plywood to spread weight loadings for 1 man and a small tool box. This system is flammable, moves under foot and will create panel delamination if fixed to the io external skin of a composite panel. Composite wall panels can achieve up to meters high! ceiling panels can achieve up to a span of 9 metres and is why they are deemed fragile surfaces.

3. The object of our walkway system will offer easy assembly, fire retardant and is anti-slip properties, all components are replaceable. Key features of our walkway system are the x4 lightweight modular sections to maintain ease of access, the system can be placed over any flat composite ceiling panel to maintain the designated walk way for maintenance engineers access purposes.

4. The system can also be supported and will be determined by appropriate existing steels to connect to.

The walkway system is installed over existing ceiling areas to insure a person’s weight is distributed evenly to eliminate the risk of an existing envelope collapsing 25 (especially for older envelope structures and/or ceiling designs where there are many cut apertures).

Claims

1. A walkway system comprising a grating on a rigid ladder frame, and a wire rope system and/or a plurality of lengths of studding for connecting the walkway

5 system to a supporting structure above the walkway system.

2. A walkway system of claim 1, including a plurality of unistruts which span under the width of the ladder frame, wherein a respective one of the lengths of studding is fixed to each end of the unistruts.

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3. A walkway system of claim 1 or claim 2, wherein the frame is formed of galvanised steel or stainless steel.

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4. A walkway system of any preceding claim, wherein the grating is formed of glass-reinforced plastic.

3. A walkway system of claim 1 or claim 2, including a retaining angle fastened along each side of the ladder frame to lock the ladder frame and grating together.

4. A walkway system of any preceding claim, wherein the frame is formed of is galvanised steel or stainless steel.

5. A walkway system of any preceding claim, wherein the grating is formed of glass-reinforced plastic.

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Amendments to the claims have been filed as follows:

Claims

1. A walkway system comprising a grating on a rigid ladder frame, a plurality of lengths of studding for connecting the walkway system to a supporting structure

5 above the walkway system, and a plurality of struts which span under the width of the ladder frame, wherein a respective one of the lengths of studding is fixed directly to each end of the struts.

2. A walkway system of claim 1, including a retaining angle fastened along each io side of the ladder frame to lock the ladder frame and grating together.