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Formaldehyde-free flooring and roofing
International Survey Flexible joints keep Snorre platform moving Metalastik, of Leicester, has designed and manufactured unique flexible joints to allow movement in the new Saga Snorre platform in the Norwegian North Sea, the world's largest tension leg platform (TLP) to date. These 'flexelements' consist of large rings of interleaved steel plates and rubber fitted at either end of the 16 giant steel tubes which tether the TLP to the sea bed. They allow the platform to move horizontally under the strain of violent storms and heavy tidal flow, without imposing excessive bending loads on the tethers. The design is fail safe, capable of withstanding the varying tension forces in the tether for up to 30 years and will accept a 30% tension overload for more than a year. In addition, all the materials used have been specially selected to resist the adverse effects of sea water. Over a 2 year development programme different materials, sizes and designs were evaluated using a variety of techniques, including three-dimensional finite-element analysis modelling, before the first, one-third-scale prototypes were ready for testing in a specially built rig. Optimum process and inspection procedures were defined to ensure a uniform cure, bond integrity and interleaf position throughout the flexelement. The final design was based on a deproteinized natural rubber incorporating 18 steel interleaves in a part spherical shape. Each weighed 3 tonnes and 41 were produced, including nine spares. The flexelements are located in the cross-load bearings at the top of each tether and in the anchor latches which connect the bottom of each tether to its anchors. The tethers are made up of special thick-walled pipes, each 17 metres long with a diameter of 812 mm. In April, last year, the platform was successfully tethered to the sea bed in a diverless installation procedure involving a fleet of tugs and a giant semi-submersible crane.
Formaldehyde-free flooring and roofing A major breakthrough in the effort to rid flooring, roofing and geotextiles manufactures of their involvement with
formaldehyde will be unveiled this spring by Rohm and Haas. Free of any formaldehyde ingredient themselves, the new water-based binders are also proof against the later emission of the chemical during the manufacture, installation or actual end use of webreinforced products - a problem of increasing concern to the industries involved. Current industrial consumption of formaldehyde is in excess of 5 million tonnes, of which more than half is used in Europe. Attempts to find an effective safe substitute have failed on grounds of physical performance, as yet. Indeed, the tensile strength imparted by the acrylic binders offers manufacturers the option of reducing fibreglass weights - and hence costs - without impairing the essential stiffness or durability of the end product. Further information from Rohm and Haas Polymers and Resins Group, telephone 081-686 8844.
Letter from the British Cement Association Dear Sirs
The Centre for Concrete Training You will recall the major re-structuring which the BCA, like so many companies in the current economic climate, was forced to undertake at the end of 1992. At that time, there was uncertainty over whether we would be able to maintain our commitment and tradition of over 40 years in providing training on concreterelated subjects to the construction industry. However, we have received a lot of support from the industry and, as a result, have established The Centre for Concrete Training. A financial plan has been drawn up which will allow BCA Courses and Seminars to continue, albeit on a slightly reduced scale. Several companies have now shown interest in sponsoring the Centre. In addition, employers continue to want the high-quality, value for money training that has always been BCA's stated policy. We are working on the Programme of Events for 1993/94 and this includes several low-cost one-day events, priced at under £100 per delegate and offering short, sharp practical advice for busy site staff, specifiers and designers. We have just installed a new computer system
which is already bringing big improvements in the service we can provide to customers. In short, we are dedicated to ensuring that U K construction continues to have a Centre for Concrete Training. Yours faithfully Maurice M. Barnes Manager, Events
Anti-condensation coating A new anti-condensation hygienic coating for ceilings and upper walls, which prevents the formation of water droplets by absorbing moisture, is being marketed by Rust-Oleum International, Roosendaal, The Netherlands. Once dry, 1 litre of applied coating will absorb at least 400 g of moisture. Known as Rust-Oieum Anti-Condensation Coating 5090, the product is intended for use in food factories, breweries, bakeries, wineries, dairies, canteens, kitchens and wherever food or drink is manufactured, prepared or sold, as well as in sports centres, wash and shower rooms and laundries. It can be used in any place where periods of high humidity are followed by relatively dry periods, which allow the absorbed moisture to evaporate and disperse by normal ventilation. The coating is not recommended for use in environments with constantly high levels of humidity. It is a water-based non-flammable acrylic polymer with a solids content of 26%, providing a durable, flat white finish which can be applied by brush, roller or airless spray, even on mineral surfaces which are slightly damp.
Roof for Bank Underground Station A 12 month project in the City of London is at present underway to re-strengthen the roof of the pedestrian subway at Bank Station, to accommodate current highway loadings and the 17 t weight restriction on the junction currently being removed by contractors Balfour Beatty Civil Engineering Limited. The first stage of each phase of the project (of which there are eight) involves the demolition of the existing roof, followed by the construction of new rein-
Construction and Building Materials 1993 Volume 7 Number 3
185
Formaldehyde-free flooring and roofing A major breakthrough in the effort to rid flooring, roofing and geotextiles manufactures of their involvement with
formaldehyde will be unveiled this spring by Rohm and Haas. Free of any formaldehyde ingredient themselves, the new water-based binders are also proof against the later emission of the chemical during the manufacture, installation or actual end use of webreinforced products - a problem of increasing concern to the industries involved. Current industrial consumption of formaldehyde is in excess of 5 million tonnes, of which more than half is used in Europe. Attempts to find an effective safe substitute have failed on grounds of physical performance, as yet. Indeed, the tensile strength imparted by the acrylic binders offers manufacturers the option of reducing fibreglass weights - and hence costs - without impairing the essential stiffness or durability of the end product. Further information from Rohm and Haas Polymers and Resins Group, telephone 081-686 8844.
Letter from the British Cement Association Dear Sirs
The Centre for Concrete Training You will recall the major re-structuring which the BCA, like so many companies in the current economic climate, was forced to undertake at the end of 1992. At that time, there was uncertainty over whether we would be able to maintain our commitment and tradition of over 40 years in providing training on concreterelated subjects to the construction industry. However, we have received a lot of support from the industry and, as a result, have established The Centre for Concrete Training. A financial plan has been drawn up which will allow BCA Courses and Seminars to continue, albeit on a slightly reduced scale. Several companies have now shown interest in sponsoring the Centre. In addition, employers continue to want the high-quality, value for money training that has always been BCA's stated policy. We are working on the Programme of Events for 1993/94 and this includes several low-cost one-day events, priced at under £100 per delegate and offering short, sharp practical advice for busy site staff, specifiers and designers. We have just installed a new computer system
which is already bringing big improvements in the service we can provide to customers. In short, we are dedicated to ensuring that U K construction continues to have a Centre for Concrete Training. Yours faithfully Maurice M. Barnes Manager, Events
Anti-condensation coating A new anti-condensation hygienic coating for ceilings and upper walls, which prevents the formation of water droplets by absorbing moisture, is being marketed by Rust-Oleum International, Roosendaal, The Netherlands. Once dry, 1 litre of applied coating will absorb at least 400 g of moisture. Known as Rust-Oieum Anti-Condensation Coating 5090, the product is intended for use in food factories, breweries, bakeries, wineries, dairies, canteens, kitchens and wherever food or drink is manufactured, prepared or sold, as well as in sports centres, wash and shower rooms and laundries. It can be used in any place where periods of high humidity are followed by relatively dry periods, which allow the absorbed moisture to evaporate and disperse by normal ventilation. The coating is not recommended for use in environments with constantly high levels of humidity. It is a water-based non-flammable acrylic polymer with a solids content of 26%, providing a durable, flat white finish which can be applied by brush, roller or airless spray, even on mineral surfaces which are slightly damp.
Roof for Bank Underground Station A 12 month project in the City of London is at present underway to re-strengthen the roof of the pedestrian subway at Bank Station, to accommodate current highway loadings and the 17 t weight restriction on the junction currently being removed by contractors Balfour Beatty Civil Engineering Limited. The first stage of each phase of the project (of which there are eight) involves the demolition of the existing roof, followed by the construction of new rein-
Construction and Building Materials 1993 Volume 7 Number 3
185