Hazardous Materials Otsu-4 | Firefighting, Spill Response, and Foam-System Cases
1 / 100.0s
Problem 1
A gasoline container cracks in an indoor loading area, and liquid flows down the sloping floor toward a storm-water drain. It has not ignited. The facility has already started its emergency notification and is assembling trained responders.
Which initial action is most appropriate to prevent ignition and further spread?
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Flushing gasoline into drainage can carry flammable vapour and environmental contamination into places that cannot be seen or controlled. Ignition sources must be removed, the area isolated, the leak stopped if this can be done safely, and the drain protected while noncombustible material contains the spill for proper recovery. Water flushing does not remove the hazard; it transfers it to an uncontrolled location.
Problem 2
A small gasoline spill has been absorbed into dry sand. Within the ignition-controlled area, a responder proposes using an ordinary steel shovel and an ungrounded powered recovery machine to transfer the absorbent into a container.
Which revision of the recovery work is most appropriate?
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Gasoline vapour can remain after absorption, and scooping or transferring the absorbent creates another opportunity for ignition. As the SDS specifies, clean antistatic tools should be used and equipment handling the spill should be grounded before recovery. Merely using metal or touching a tool to the floor once does not ensure continuous control of potential differences during the work.
Problem 3
A small pool of gasoline is burning on the floor, and sealed metal containers immediately beside it are being heated by the flames. An agent rated for flammable-liquid fires and a water supply that can produce a spray are available, and an escape route has been secured.
Which use of the available agents best combines extinguishment with exposure protection?
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A solid water stream directed onto burning gasoline can spread the burning liquid. Water nevertheless has a separate role in cooling exposed containers, limiting pressure rise and fire spread. The fire should therefore receive a suitable extinguishing agent while solid-stream application to the liquid is avoided and immovable exposed containers are cooled with water spray. The blanket claim that water has no role at all is also incorrect.
Problem 4
A gasoline-fire response plan has already confirmed the suitability of its foam agent and the escape route. However, responders have only cotton workwear and particulate masks, and the plan permits them to approach the fire whenever little smoke is visible.
Which assessment of this entry plan is most appropriate?
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A gasoline fire can expose responders to flammable vapour and harmful combustion products. Selecting a suitable extinguishing agent does not remove this exposure hazard. The SDS calls for appropriate self-contained breathing apparatus and chemical protective clothing for firefighting. A particulate mask is not gas-and-vapour respiratory protection, and protective equipment alone does not authorise an untrained employee to enter a dangerous area.
Problem 5
A self-service filling station proposes moving the agent container for its packaged fixed foam system from an equipment room to a temporary outdoor shelf. The shelf reaches 43°C in summer, receives direct sunlight and rain, and has no hardware to secure the container.
Which decision is most appropriate in light of the container-location requirements?
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For this system type, the agent container must be placed where fire exposure is limited, temperature variation is small, the temperature is not expected to exceed 40°C, and direct sunlight and rain are unlikely; it must also be secured against movement or overturning during an earthquake or similar event. The proposed shelf fails several conditions. Neither the fill quantity nor a pressure rating makes agent-condition control and safe siting unnecessary.
Problem 6
A self-service filling station changes its vehicle route and moves the marked stopping position sideways. The discharge outlets for its packaged fixed foam system are not moved, and an edge of the new stopping position may fall outside the existing effective discharge range.
Which review is most appropriate when making this layout change?
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A packaged fixed foam system is not adequate merely because it can discharge somewhere within the station. Its outlet arrangement must make the effective discharge range encompass a marked vehicle stopping position. Moving that position changes the relationship between the protected area and the installed system. Coverage should be confirmed from tests or specifications, followed by any necessary equipment revision and regulatory procedure.
Problem 7
A packaged fixed foam system stores a premixed solution of foam agent and water. No discharge test has been performed for a long period, but the level indicator reads full and there is no visible external leak.
Which decision about continued use is most appropriate?
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A premixed foam solution must retain not only its quantity but also the properties required for extinguishment. Appearance and a level indicator do not establish foaming or fire performance. Inspection points and acceptance values must follow the agent and system specifications, with servicing or replacement when they are not met. Adding water without a technical basis may instead move the solution outside its specified concentration.
Problem 8
A small leak is found at a joint in a solvent-supply system. The same system's automatic high-level shutdown has been bypassed because it occasionally malfunctions, and the facility proposes installing a larger catch tray and restarting under continuous operator observation.
Which restart condition is most appropriate?
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The leaking joint and bypassed automatic shutdown represent the simultaneous loss of separate protective layers. A catch tray and operator observation may reduce some consequences after release, but they are not permanent substitutes for preventing leakage and reliably stopping a high-level condition. The leak cause must be repaired, and the shutdown and alarm functions restored and tested before operation resumes.
Problem 9
An organic-solvent tank has been drained and its manway left open overnight. The next morning, workers plan to grind nearby piping without isolating the connected lines or cleaning the tank, relying on a low reading taken outside the opening the previous day.
Which condition must be met before spark-producing work begins?
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After draining, hazardous material may remain in tank recesses, on surfaces, or in connected piping and may generate flammable vapour again. A past measurement outside the opening cannot establish conditions throughout the vessel at the time of work. Piping must be isolated, residues removed, safe ventilation provided, and concentrations checked at the locations and times required by the facility's work-permit procedure before hot work is authorised.
Problem 10
During a power failure, a gasoline-powered emergency generator is supplying a critical load but is running low on fuel. An operator proposes switching it to idle and refuelling through a funnel while it continues to run because stopping it would be disruptive.
Which decision best reconciles continuity of supply with refuelling safety?
View explanation
An operating generator has hot surfaces and electrical ignition sources that can ignite spilled gasoline or vapour. Idling and using a funnel do not remove those sources. If the critical load cannot simply be interrupted, the operational control is to arrange an alternative supply or a safe planned shutdown in advance. The generator can then be stopped and refuelled only after the cooling and refuelling requirements in its instructions are met.