Monthly Archives: June 2015

Why Composite Manhole Covers?

During the pre-2011 Elections, there were negative press reports on exposed manholes and these reports highlighted injuries, accidents and in some cases deaths. The exposed manholes were blamed mainly on vandalism & theft of iron cast manhole covers.

In February 2011, wnm limited requested and was granted audience by Lagos State Public Works Corporation (LSPWC) where the company proposed Secure Composite Cover solution and was subsequently given the opportunity to execute trials. January 2012 wnm limited presented to the Governor of Lagos State and on approval of the proposal to State Tenders Board.

Phase 1 installations consisting of 215 installations of Manhole covers and Gratings commenced in August 2012 and was completed in January 2013 and in February 2013, Phase 2 consisting of 350 installations of Manhole covers and Gratings was completed in January 2014. wnm limited has just recently concluded the phase 3 installation of composite manhole covers and gratings for the Lagos state government, installing composite manhole covers where the steel covers are either damaged or stolen. The project comprised of the installation of 119 manhole covers and 373 gratings in total.

What are Composites?

Composites are products made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with different characteristics to those of the individual components.

Why Composite Manhole Covers?

  1. Composite Manhole Covers Have No Secondary Market Value and Deters Theft

Cast iron and metal manhole covers are stolen for their scrap value thereby causing safety issues for the general public. Composite Manhole Covers offer a quick, easy and affordable way to prevent manhole cover theft. Composite manhole covers have no secondary market value thereby deterring theft and ensuring safer roads.

  1. Composite Manhole Covers Are Ideal for Corrosive Environments

Sewer and wastewater systems can be highly corrosive. Composite manhole covers do not melt, crack, bend or rust in extremes of environmental elements such as sand and salt water. Also, the composite manhole covers remain unaffected in temperatures even up to 200°F. This inherent corrosion resistance makes composite manhole covers ideal.

  1. Composite Manhole Covers Require Low Maintenance, Reduce Operation Costs and Save Energy

Composite manhole covers and lids require less labour, time and equipment to install and maintain. Composite covers reduces on vehicle weight, fuel consumption and trips required to maintain the covers, in the sense that composite manhole covers weigh less than cast iron manhole covers. The composite covers do not require the significant maintenance or replacement costs of the iron cast manhole covers. Composite manhole covers require very little maintenance to keep them looking clean as they cannot be damaged by traditional problems such as rot, moss and mould.

  1. Composite Manhole Covers Reduced Weight = Reduced Worker Injuries

Thanks to the engineered nature of these products, it is possible to produce largely hollow (and therefore extremely light) elements that are almost as strong, if not stronger, than solid elements made from more traditional materials. Certainly, in most instances the strength of composites is superior to that of traditional materials.

Due to the fact that the composite manhole covers are lightweight, they are easier and safer to handle and put in place. This reduces the record of worker injuries as the manhole cover is more lightweight than the traditional iron cast covers.

  1. Composite Manhole Covers Are Ideal for Non-Conductive Applications

Many Telecommunication companies and electrical utility manhole applications require manhole lids and rings to be non-conductive. Composite manhole lids are well suited for these non-conductive manhole requirements. Manholes can also be fabricated and fitted with non-conductive fiberglass ladders, platforms and railings.

  1. Composite Manhole Covers Are Fully Traffic Weighted.

Composite manhole covers have low deflection and minimal permanent set even under high loads up to 40 tonnes (class D400).  Manufactured to; BS EN 124 Standards and ASTM E-84 Standards.

Our composite manhole covers are secure, locked into place with our secure bolts and keys that prevent unauthorized access. They are also available in different colours which increases safety awareness in industrial environments.