CONFERENCE CASE STUDY
INGENIEUR
CONFERENCE CASE STUDY
INGENIEUR
Managing Risks in Confined Space Entry - Offshore Oil & Gas Platform
By Ir . Teo Eu Jin
Confined Space Entry ( CSE ) is common for industries that utilise Pressure Vessels or Storage Tanks in their facilities for the purpose of Inspection , Maintenance or Repair , such as offshore Oil & Gas Platform and Onshore Chemical Refinery . “ What is Confined Space ”? There are many versions of explanation in the Internet . However , for industries in Malaysia , we refer to legislation from the Department of Occupational Safety and Health ( DOSH ):
● Factories and Machinery ( Safety , Health and Welfare ) Regulation 1970 , Section 13 on Confined Spaces .
● Occupational Safety and Health Act 1994 , Part X Industry Codes of Practice , and subsequently to the Industry Code of Practice for Safe Working in Confined Space 2010 .
According to the “ Industry Code of Practice for
Safe Working in Confined Space 2010 ”: “ Confined space ” means an enclosed or partially enclosed space that is at atmospheric pressure during occupancy and is not intended or designed primarily as a place of work , and – a ) is liable at any time to – ( i ) have an atmosphere which contains potentially harmful levels of contaminants ; ( ii ) have an oxygen deficiency or excess ; or ( iii ) cause engulfment ; and b ) could have restricted means for entry and exit . Also , highlighted by this Industry Code of Practice , a person whose head or upper body is within a confined space is considered to have entered the confined space .
Clearly CSE is hazardous in terms of the working environment where one may be more hazardous compared to another , but the general precaution remains the same . For example , entering a huge
CSE sewage system versus a medium size Pressure Vessel may possess different risk level . Thus , it is essential to identify the hazards and manage the risk by considering both preventive measures and necessary mitigation ( Bow-tie Analysis ). In accordance to the common “ Hierarchy of Control ” in the event that CSE task is unavoidable , meaning unable to go for “ Elimination ” and “ Substitution ” of this hazardous scope , hence one can manage the risk through “ Engineering Control ”, “ Administrative Control ” and Personal Protective Equipment ( PPE ).
Let us begin with Engineering Controls for facilities that involve Pressure Piping , Pressure Vessel and associated pressurised components that are in operation mode . Prior to any CSE it is crucial to depressurise the system by manipulating the associated upstream and downstream valves , then bleed the remaining stored pressure followed by Zero Energy confirmation via pressure gauges . For better safety precaution in avoiding medium entering the confined space through passing valves ( if occur ), it is wise to install physical barriers either by dropping the connecting pipe spools then blind the flanges or installing rated spade in between the pipe flanges by competent riggers via valid rigging gears .
If there are hazardous residue in the Confined Space , one or more initial cleaning method can be performed single or multiple times outside the Confined Space such as [ i ] Soaking ( Chemical Solvent ), [ ii ] Draining the content , [ iii ] injecting Purging Agent ( e . g . N2 Inert Gas ) and [ iv ] Flushing . The cleaning medium used needs to be suitable without adverse effect to the process line . Also , ventilation can be used to assist initial cleaning . The ultimate goal is to reduce the hazardous contaminant to the lowest level . No CSE should be allowed if Atmospheric Gas reading exceeds the
56 VOL 96 OCTOBER-DECEMBER 2023