On 25 July 2024 the US Chemical Safety and Hazard Investigation Board (CSB) published a safety study titled Remote Isolation of Process Equipment. It reviews several incidents the CSB has investigated, including the Intercontinental Terminals Company tank fire, the Philadelphia Energy Solutions refinery fire and explosions, and the TPC Group explosion at Port Neches, all in 2019. Its conclusion is that the chemical industry has not fully recognised how critical effective remote isolation is to stopping releases of hazardous materials quickly (U.S. Chemical Safety and Hazard Investigation Board [CSB], 2024a). In the Philadelphia refinery fire, roughly 676,000 pounds of hydrocarbons and more than 5,200 pounds of hydrofluoric acid were released, and property damage was estimated at US$750 million (CSB, 2024a).
The message matters in Indonesia, where tanks and piping holding flammable or toxic materials sit in refineries, fuel terminals, chemical plants and solvent stores across industrial estates. This article sets out a simple method to judge whether a piece of equipment needs a valve that can be closed remotely or automatically.
Emergency Isolation Basics
When something leaks, the speed at which the flow is stopped decides the size of the release. The CSB study cites API RP 553, which sorts emergency block valves into four types. Type A is operated by hand at the equipment. Type B is also manual and fire-safe, installed at least 7.6 m from the leak source. Type C is a power-operated Type B with controls at the valve. Type D is remotely controlled, with its controls at least 12 m from the leak source and outside the fire zone (CSB, 2024b). The CSB states that Type A, B and C valves serve no reliable function in catastrophic incidents, because they often cannot be safely reached (CSB, 2024b).
The UK Health and Safety Executive (HSE) calls these remotely operated shutoff valves (ROSOVs), and calls versions that close on a detector signal automatic shutoff valves (ASOVs) (Health and Safety Executive [HSE], 2004).
Five Assessment Steps
The steps below are our synthesis of the five stages in HSE guidance and the Center for Chemical Process Safety (CCPS) decision tool reproduced in the CSB study.
- Identify the hazards. Gather the safety data sheets and decide whether the substance is flammable, toxic, corrosive or a mix. For dual-hazard substances, assess each hazard separately and adopt the higher standard (HSE, 2004).
- Screen with key questions. The CCPS tool cited by the CSB asks whether the material is flammable, whether the inventory is below 2,000 gallons, whether it is toxic or corrosive, whether it runs at elevated pressure, whether it operates near its flash point or is a liquefied gas, and whether it sits in a fire-sensitive area. CCPS guidance also says equipment with flammable gas or liquid inventories above 5,000 gallons, about 19 m3, should have emergency isolation valves (CSB, 2024b).
- Assess the risk, including response time. HSE asks for operator response to be broken into detection, diagnosis and action, allowing time to put on PPE and recognising that operators may hesitate to shut a valve if they fear criticism afterwards (HSE, 2004).
- Record the findings and the reasoning, especially when the decision is not to fit a remote valve where the criteria point to one as good practice (HSE, 2004).
- Fit the valve where reasonably practicable and review the assessment periodically, since changes in capacity, nearby population or the cost of technology can change the answer (HSE, 2004).
A Worked Example
This example is illustrative, not a real case. A plant keeps 25 m3 of flammable solvent in a day tank feeding a transfer pump inside the production building. That is roughly 6,600 gallons, above the 5,000-gallon figure in CCPS guidance (CSB, 2024b). The manual valve at the tank outlet sits inside the bund, so no one can approach it once a leak has ignited. Working through the steps, the plant team would arrive at a Type D valve that can be closed from the control room and closes itself when a fire detector trips, backed by a function-test schedule.
In Indonesia this assessment fits within Minister of Manpower Decree No. KEP.187/MEN/1999 on the control of hazardous chemicals in the workplace. The decree sets threshold quantities, for example 100 tonnes for highly flammable liquids and 50 tonnes for flammable gases (Article 14). Companies above them are classed as having major hazard potential (Article 15) and must prepare a major hazard control document (Article 16) covering, among other things, hazard identification and risk control, installation design and operation, and emergency response plans (Article 19) (Departemen Tenaga Kerja [Depnaker], 1999). The isolation valve assessment belongs in that document.
Where It Stops
We see this screening tool as a way to set priorities, not a substitute for process hazard analysis such as HAZOP or LOPA. The gallon figures in CCPS guidance reflect US industry practice and are not legal requirements in Indonesia. Remote valves can also fail: HSE (2004) lists failure to close because of poor maintenance and testing, internal leakage from wrong specification, untrained operators, and valves disabled by the fire itself. An isolation valve therefore needs to be managed as a barrier that is proof-tested, not fitted and forgotten. HSE also makes clear that concern over spurious trips is not, on its own, a reason to leave out an ASOV (HSE, 2004).
How Nusa Safety Helps
Nusa Safety can help companies build emergency isolation assessment into HAZOP and LOPA studies, review barrier readiness and function testing through a Process Safety Management Review, and prepare a Major Hazard Control Document for companies above the threshold quantities.
This article is general information and not legal or professional advice for any specific case.
References
- Departemen Tenaga Kerja. (1999). Keputusan Menteri Tenaga Kerja Nomor KEP.187/MEN/1999 tentang Pengendalian Bahan Kimia Berbahaya di Tempat Kerja [Minister of Manpower Decree No. KEP.187/MEN/1999 on the control of hazardous chemicals in the workplace]. https://jdih.kemnaker.go.id/peraturan/detail/2608/keputusan-menteri-nomor-187-tahun-1999
- Health and Safety Executive. (2004). Remotely operated shutoff valves (ROSOVs) for emergency isolation of hazardous substances: Guidance on good practice (HSG244). HSE Books. https://www.hse.gov.uk/pubns/books/hsg244.htm
- U.S. Chemical Safety and Hazard Investigation Board. (2024a, July 25). U.S. Chemical Safety Board releases new study calling for greater use of remote isolation equipment at chemical facilities [Press release]. https://www.csb.gov/us-chemical-safety-board-releases-new-study-calling-for-greater-use-of-remote-isolation-equipment-at-chemical-facilities/
- U.S. Chemical Safety and Hazard Investigation Board. (2024b). Remote isolation of process equipment (Safety Study No. 2024-01-H). https://www.csb.gov/assets/1/6/CSB_RIPE_Study_Finalv.pdf
