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Maintenance of BS EN124-2 Ironwork

Under normal UK climatic conditions and non-aggressive chemical environments, e.g. Highway applications, BS EN124-2 ironwork products generally require little maintenance due to the inherent corrosion resistance to sectional perforation. Indeed, following loss of the industry-standard aesthetic coating due to trafficking abrasion, cast irons covers usually produce a fine oxide film on their surface that deters further oxidation of the underlying parent metal. This results in the cover and frame sections lasting many decades and which can be successfully recoated to increase longevity and improve aesthetic appeal.

  1. Maintenance of Manhole Tops

    1. Coatings
      Manhole Tops are usually supplied with a factory-applied barrier paint coating or bitumen paint for transit and short-term aesthetic appeal. These coatings offer no galvanic protection to the ironwork, unless specifically agreed otherwise in the contract. Such coatings may be applied and re-applied throughout the life of the product, according to aesthetic requirements. For interim applications of repair coatings, Wrekin recommend the use of brush or spray applied; Thomas Howse QAD P0090 Paint (MSDS HS1). - Please see separate on-site application of coatings document. 

      N.B. When applying a repair coating, ensure provision of any necessary safety measures, including PPE, and ensure the application method is suitable for the surroundings as well as the ironwork.

    2. Cleaning
      Where chamber access is gained by the temporary removal of cover elements, it is always good practice to remove any debris from and brush-clean all contact points between the cover and frame components. At the same time, the remaining debris in any Lifting Keyways can be cleaned-out by inverting the cover element(s). This cover inversion procedure also allows the loose-link fastener components between double-triangular covers to be inspected and replaced, where they indicate any signs of distress. Similarly, this is also a good time to conduct an inspection of the cover(s) structural support beams.

      N.B. When contacting Wrekin to order replacement locking components or loose-link fasteners for double-triangular covers, please photograph the cover pair (top and underside view) and note the text markings on the cover top surface as these can be useful for positive product identification.

  2. Maintenance of Gully Gratings

    1. Coatings
      As per Manhole Tops, Gully Gratings are usually supplied with a factory-applied barrier paint coating or bitumen paint, for transit and short-term aesthetic appeal. These coatings offer no galvanic protection to the ironwork, unless specifically agreed otherwise in the contract. Such coatings may be applied and re-applied throughout the life of the product, according to aesthetic requirements.

    2. Cleaning
      Where gully chamber access is gained by the temporary removal or hinging of the grating element(s), it is always good practice to remove any debris from and brush-clean all contact points between the grating and frame components. This cover inversion procedure also allows the loose-link fastener components between double-triangular covers to be inspected and replaced, where they indicate any signs of distress. N.B. When contacting Wrekin to order replacement components, please photograph the grating (top and underside view) and note the text markings on the grating top surface as these may be requested by Wrekin personnel for positive product identification.

    3. Condition Assessment
      If the ironwork product is being inspected due to noisy or unstable operation resulting from foundation or chamber deterioration, before re-installing it, the component parts of the ironwork should be examined for signs of cracking. Where cracks are revealed in the grating [underside] structural support beams or frame seats, such assemblies should be replaced with completely new products and not reused. N.B. Cracks in ironwork are usually evidenced by preferential oxidation of the crack fissure resulting in corrosion residue (rust) being deposited around the it. If the inspection is due to excessive ‘grating-drop’ in the frame, then unless the product has replaceable seating components, the whole assembly will have to be replaced.

  3. Accessory Parts

    1. Flood & Odour Control Plates (F&OCP) and Low Leak Seal Plates (LLSP)
      F&OCP are factory-fit accessories located under manhole top frames of which, only their chamber-access lid fasteners are replaceable. Routine cleaning is not required but it is beneficial for the F&OCP top surface to be brush cleaned following removal of the manhole top cover elements in order to remove accumulated corrosive media and to facilitate access to the F&OCP removable lid component.

      LLSP (Unite-Evo & Highway brands only) are a factory or retro-fit accessory located inside the frame component of a manhole top assembly and are replaceable. Routine cleaning of the LLSP is not required except where hydrocarbon spillage is likely to have contaminated the elastomeric seal element (as this can cause swelling and dislodgement of the seal) in which case, the LLSP should be cleaned using a mild soap-based detergent prior to re-coating the elastomeric seal with a drinking water compatible Silicone grease or grease compliant to BS6920.

      N.B. When contacting Wrekin to order a replacement LLSP, please photograph the item in-situ and note the text markings on the manhole top surface as these can be useful for positive product identification.

    2. GritBlocker
      GritBlocker is a factory or retro-fit accessory which may be inserted into a clean, closed-cavity Lifting Keyways of a manhole top in order to prevent it filling with detritus that might otherwise prevent Lifting Key insertion. When inserted into a Lifting Keyway, GritBlocker requires no routine maintenance other than removal of any debris that may have collected above it (during service), prior to Lifting Key insertion.

    3. Resilient material seating inserts and seals
      These can be removable parts or feature of an ironwork assembly that act as the intermediate contact or seal between the cover and frame components. The removable parts are usually of a non-metallic material (e.g. rubber, etc.) and are often designed to be replaceable where found to be worn out. Otherwise, no routine maintenance is required but good practice should ensure that they are cleaned with a mild detergent, in-situ, whenever cover or grating elements are opened/removed for chamber access. If seatings are also intended to act as or form a seal (including labyrinth* types), once cleaned, they should be re-coated (or filled*) with a drinking water compatible Silicone grease or grease compliant to BS6920.