With recent RIDDOR statistics attributing over half of injuries (resulting in absence from work) to manual handling it’s already known that reducing hazards in this area is a priority on a global scale.
Because of legislation restricting acceptable manual handling weights, we are seeing a global trend towards lighter weight GRP composite (glass reinforced plastic) manhole and access cover materials, which also have the benefits of ease of handling and corrosion resistance.
Lightweight composite covers that provide safe and easy access eliminating unsafe manual handling issues are replacing aging concrete and heavy cast iron access covers all over the world. By using lighter materials, operational injuries are prevented, work sites are made safer and ease of installation and maintenance is made available to utility workers and contractors.
Composites are also becoming highly attractive as a result of the metal theft epidemic as they provide the perfect solution – they won’t be stolen for their resale value.
A major problem across the globe is our aging infrastructure. Across the world, bridges, highways, rail lines, water lines and sewer systems are deteriorating at a rapid pace. One of the principal factors related to the deterioration of infrastructure is corrosion.
According to a study by the National Association of Corrosion Engineers (NACE), the direct cost of infrastructure corrosion was over $22 billion in 2002 in the United States alone. Adjusted for inflation, the direct cost of corrosion in 2013 is estimated to be over $42 billion on an annual basis. It has been estimated that at least 25% to 30% of annual corrosion costs could be saved if optimal corrosion management practices were employed.
GRP products are now being widely used for applications where corrosion can destroy underground infrastructure. Perhaps the prime reason for using GRP products is because of their inherent corrosion resistance. In many cases, they are the only materials that will handle a given service environment; and in other cases their corrosion resistance is combined with their lower unit cost to make them the most economical acceptable solution (such as when compared to high grade stainless steel). Corrosion resistance of GRP is a function of both the resin content and the specific resin used in the laminate. There are various resin systems available today which provide long-term resistance to almost every chemical and temperature environment.
Composite manhole covers, such as those produced by Fibrelite, are highly resistant to all forms of corrosion. For this reason, they have been specified for use in highly corrosive environments such as steam manhole vaults. In many major cities, district energy networks operate large underground piping systems used to transmit steam from a central plant to nearby office buildings, hotels, hospitals and apartments. The steam or superheated steam that is transmitted in such systems can often reach temperatures as high as 300° F. Due to the high heat of the steam, many utilities require the use of a thermally non-conductive composite manhole cover to prevent the accidental burning of pedestrians that may come in contact with the cover.
A combination of failing fall-restraints and cover segments weighing in excess of 70kg made the health and safety risks unacceptable on this particular combined sewer overflow (CSO) site. Following research into various alternatives, this water company saw Fibrelite as the preferred partner to help eliminate on-site dangers associated with their metal manhole and trench access.
With no need for hinges or mechanical parts there is no potential for failure and no requirement for ongoing maintenance - the Fibrelite GRP composite trench cover is a ‘fit and forget’ product. What’s more, with weight lifted not going beyond 25kg, Fibrelite ticked all the boxes in terms of health and safety.
By helping to reduce the costs of corrosion, composite covers can allow municipalities, utilities and other operators of underground infrastructure to improve the financial strength of their enterprises.
