9.3 Plugging and Patching

9.3 Plugging and Patching

Quick Answer: Plugging and patching are offensive containment: stop product in the original container. NFPA 470 (2022) 11.4.3.2 is controlling container leaks. Center for Domestic Preparedness (CDP) and TEEX technician skills still use the 55-gallon drum: bung leak, chime leak, nail or forklift puncture, then wooden plugs, mechanical clamps, patches, epoxy putty, or drill-and-tap / screw plugs. Compatibility of the plug with the product is not optional. Pressure and remaining product decide whether the attempt is safe. Do not plug a BLEVE-candidate pressure vessel as a first thought. Sequence: identify → PPE → control ignition → uphill/upwind approach → mechanical control.

Section 9.1 drew the line: this is the walk-up. Section 9.2 still runs in parallel — dike the dock while the entry team works the hole. OSHA 1910.120(q)(6)(iii) exists specifically so technicians approach the point of release to plug, patch, or otherwise stop the release, within unit resources and PPE. A perfect wedge in the wrong suit is not a pass.

What the drum-leak skill is actually testing

The workhorse nonbulk liquid package is the 55-gallon (208 L) drum (Chapter 4). Skills manuals built on NFPA 470 11.4.3.2 (TCFP Chapter 6 product control, CDP PER-272 drum leak, TEEX HAZ020) expect you to recognize the failure and pick a tool that matches it:

Open-head versus tight-head matters. A tight-head (1A1 / 1H1) drum is a liquid can with bungs. An open-head (1A2 / 1H2) drum has a removable lid and closing ring. A lid leak is a ring-and-gasket problem; a sidewall puncture is still a plug/patch problem. Overpacking (9.4) is how you retire a drum that will not take a trustworthy mechanical fix.

Compatibility, swell, and what the wedge is made of

There is no universal plug. Wood is common in CDP/TEEX kits because it is cheap, carvable, and swells in many water-based liquids, tightening the seat. Hydrocarbons may not swell the same wood. Some corrosives attack wood, rubber, or the epoxy’s resin. Aluminum tools and plugs are the wrong family around some halogenated or strongly caustic products. Gaskets in patch kits are nitrile, Viton-type fluoroelastomer, neoprene, or PTFE for a reason — grab the gasket the manufacturer chart allows for this chemical, not the one that is on top of the bag.

Epoxy putty is containment only if it bonds, cures in the temperature you actually have, and does not react with the lading. Putting “the gray stick” on an oxidizer or a hot product because it worked on a training water drum is how you add a fire to a leak.

Inflatable bags and pneumatic pipe plugs need a rated pressure well above what is in the line, a compatible bladder, and a way to keep the bag from launching. They are not toys for a 331 liquid line.

Pressure and remaining product — when plugging is unsafe

Atmospheric and very low-pressure drums, totes that have already vented to nearly empty-head, and drip leaks from fittings are the usual plug/patch set. Ask:

• How much energy is left? A drum that is full, warm, and still generating vapor can push a wedge back out and spray the entry team. A nearly empty drum with a pinhole is a different problem.
• Is this a pressure vessel? Cylinders, ton containers, MC 331 tanks, and rail pressure cars store energy in the lading. Improvised wood on a chlorine valve is not a kit. Chlorine Institute Kits A/B/C, dome clamps, and pressure-isolation tools live in Chapter 10. This section’s rule is simpler: do not plug a BLEVE-candidate pressure vessel as a first thought. Fire on the vapor space, rising sound at relief valves, and tank deformation are withdrawal problems.
• Will the repair make behavior worse? Sealing a drum that is reacting internally or over-pressuring can turn a leak into a rupture. Sometimes the IAP is controlled venting under a suppression blanket, transfer (11.4.3.4, next chapter), or overpack, not a hermetic patch.

If risk versus gain says no, you still confine (9.2) and you still isolate. That is a technician decision, not a failure to “be offensive.”

Sequence: identify, PPE, ignition, approach, then tools

CDP/TEEX drum lanes fail candidates who run at the hole with a wedge in hand. Teach this order and keep it:

1. Identify the product and the container (papers, SDS, marks, drum type). Unknowns stay at Level B-or-better entry rules from the PPE chapters; you do not pick wood versus Viton in the dark.
2. Select and don PPE with a buddy, including the respirator the atmosphere actually requires. Product control is not a reason to drop to Level D because the leak “looks small.”
3. Control ignition if the material is flammable or the atmosphere can get there: shut off nearby engines, kill non-essential electrical, ground/bond if you will move or transfer product, foam the pool if vapor suppression is in the IAP.
4. Approach from uphill and upwind when the site lets you. Liquids run downhill; vapors ride the wind. A drum on a slope is an uphill problem even if the camera shot looks better from the other side.
5. Mechanical control: smallest effective plug, then a patch or clamp if the hole will not hold, then evaluate. Do not stand in the product to get a better swing.
6. Check effectiveness, report to the hazmat branch, and be ready to overpack (9.4) if the repair is a drip waiting to happen. Decontaminate tools that touched the lading.

Drive plugs only as far as needed. A wedge through the far wall is a second leak. On a training drum filled with water the instinct is to hammer; on a solvent drum the instinct should be seat, stop, look.

What this section is not

It is not Kit A on a 150 lb chlorine cylinder, not a dome clamp on an MC 306/406, and not product transfer with grounded hoses. Those are still containment, and they have their own JPRs in Chapter 10. If the stem is a 55-gallon steel or poly drum on a loading dock, stay in this toolbox: wrench, wood, patch, clamp, putty, screw plug, then salvage drum.

Scenario: TEEX/CDP 55-gallon drum, two holes

The skill station is a labeled flammable liquid tight-head drum. Hole one is a bung weeping because the plug is loose — bung wrench first, not a sidewall patch. Hole two is a forklift oval in the lower third with product still in the drum. IAP: ignition control, PPE, dike the pad (confinement), rotate only if the IAP allows moving a damaged liquid drum (often you plug in place). Select a compatible tapered plug, seat it, back it with the patch kit if the oval will not stay round, then decide whether this drum is trustworthy enough to roll or whether 9.4 overpack is the containment that actually leaves the scene. If the same station were an unlabeled pressure cylinder in a fire, you would not open the wood kit.