In order to mitigate the risk of explosions in FBOs’ underground telecommunication infrastructure due to accumulated gases and to improve the safety of operation of property in connection with all underground plant and associated installations, FBOs that are licensed to deploy underground telecommunication infrastructure shall comply with the below manhole covers requirements:

  1. seal all underground ducts leading into the manhole, used and unused, with duct plugs or suitable materials1 to ensure that no gas will pass through the ducts leading into the manhole; or

  2. install a manhole cover that is designed to fulfil the following requirements:

    1. there should be at least four (4) gas discharge valves to ensure that there are sufficient vents to allow gas to be discharged from the manhole;
    2. the gas discharge valves should be able to release gas automatically once the manhole is accumulated with gas; and
    3. the gas discharge valves should have caps so as to minimise the risk of mosquitoes getting into and breeding inside the manholes. The caps should be secured to prevent them from being dislodged; or

  3. install any alternate manhole cover that is designed to fulfil the following requirements:

    1. allow gas to be discharged from the manhole and prevent gas accumulating in the manhole;
    2. maintain the structure of the manhole cover and not compromise the current loading; and
    3. prevent the breeding of mosquitoes.

For the details of the above requirement, FBOs may email to interconnect@imda.gov.sg.

 


1Suitable sealing materials may include Resin Pack 7A or Compound 16A, or suitable alternatives such as cement mortar, silicon and polyurethane foam.

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Last updated on: 08 Sep 2022