Rhino Becomes exclusive licensee for arch profile blastwalls and stainless steel explosion relief panels for emerging technologies – May 2019
The technology owned by Inoventech Ltd and extensively used in Europe, Azerbaijan, Far East and Australia has seen further development and is now exclusively licensed to Rhino Systems Ltd on a worldwide basis. Rhino systems Ltd is able to manufacture products and supply prefabricated units to customers worldwide. This follows on from the partnering agreement signed last year with Rapp Bomek that permits both companies to provide offshore doors and blast wall/escape tunnel solutions.
The patented arch profile tackles the problem of the onset of local buckling that hitherto has limited the capacity for ductile bending of large corrugated profiles. It is available for design blast pressures up to 4 bar and spans to 13m. Typical allowable ductility ratio of 3 significantly reduces required static strength for specified dynamic blast resistance and reduces profile thickness and support reactions.
The way this is achieved is shown Figure 1 which illustrates the progressive development of the concept over time. Double sided arch profiles are also available.
Figure 1: principals of arch profile corrugated walls
The use of thinner material makes the use of austenitic and high strength duplex stainless steel economic. Not only does this improve the longevity of safety critical blastwalls in corrosive marine environments but the higher temperature resistance enables temperatures up to 1100C to be withstood without the need for passive fire protection.
It ensures competition with carbon steel bulkhead walls which, due to their load-bearing function, are limited to temperature rise of 450-550C, thereby requiring the use of PFP. This is illustrated in Figure 2, produced by UK steel construction Institute (Fire and Blast Information Group).
Figure 2 why arch profile blastwalls have higher temperature resistance than bulkhead walls.
The arch profile walls are roughly half the overall depth of equivalent bulkhead walls due to absence of main vertical beams. This has space saving advantages for platform equipment layouts.
Compliant supports are part of the supplied walls and are particularly easy to incorporate into topsides structures and can be installed later in the build process, allowing extended blast design optimisation.
In project terms main blastwalls are supplied as part of a package which includes cladding walls, which are usually stainless steel and are also offered by Rhino Systems Ltd.
Explosion Relief Panels and walls
Explosion relief panels are offered for various applications:
- Gas compressor buildings.
- Hydrogen fuel cell charging stations and nuclear power plant.
- Engine room protection for LNG and hydrogen powered ships.
- Blast mitigation for enclosures in arctic areas.
ERPs can be supplied in prefabricated cassette form or in kit form like conventional wall and roof cladding in lengths up to 6m. Cassette form has integral beams capable of spanning up to 6m and kit form has beams for spanning between normal C section purlins but with integral lateral stabilisers for the purlins.
The opening principal of the proprietary ERP of 1100mm width is shown in Figure 3. Other widths are available.
Figure 3 showing opening principal for Rhino Systems hinged explosion relief cassettes.
Hinged ERP’s are more effective in relieving explosion pressures than conventional cladding as they open up wall area for venting earlier in the explosion process. This is demonstrated by FABIG Technical Note 2, “Explosion Mitigations Systems” Ch. 5.
The ERP’s have the added advantage that harmful projectiles are avoided, thereby limiting damage spread and injury risk in explosions and has been demonstrated in tests.
Figure 4 shows the cassette based system shown in Fig 3 for use on hydrogen refuelling stations, destined for use on converted ISO containers or bespoke higher strength module options (which incidentally can be supplied by Rhino Systems complete with doors). The explosion relief panels cover the whole roof and are delivered as a single large cassette which incorporates roof beams to provide simple structural replacement for the conventional corrugated roof which is removed.
For emerging green energy solutions the high speed relief roofs for very reactive hydrogen have been developed for ISO containers. The designs are currently under evaluation by GexCon in Norway based on the international HySEA project. These high speed panels reduce peak pressures in the protected modules, compared to conventional ERPs.
Figure 4 transverse section through roof of converted ISO container for relief of hydrogen explosions
Figure 5a and 5b show cassette form ERPs certified for use in a gas compressor station (external and internal view) these units have additional requirements for fire protection and sound reduction, as sometimes required for buildings located near communities. They have external beams with downward projecting flanges which provide extra assurance against projectiles and protection of ice build-up from freezing rain.
ERPs have been subject to full scale explosion tests at GexCon’s test site in Norway.
Figure 5a 5b 5c ERPs for gas compressor stations and for engine room protection in gas powered ships (Norway)
For LNG or H2 gas powered ships (Figure 5c), ERPs relieve into void spaces which communicate to external shipside mounted ERPs located above uppermost watertight deck (also Rhino supply).