Technical Rescue in Storm Drains: Technical Rescue Usar 0

Technical Rescue in Storm Drains

Your rescue team has been asked to assist a federal law enforcement agency with a search for a missing child. It has been more than a year since she was last seen; clearly, this is not a rescue mission. You’ve been asked to search the storm drain system, which is more than 1,750 feet long and has an active creek running through it. Due to the running water and evidence preservation concerns, entries will be made by teams of rescue techs partnered with a law enforcement dive team member.

A storm drain system is a confined space. Is your agency prepared to perform confined-space search and rescue in a similar situation? Do you know what to do in the event of an engulfment situation? What type of basic training is required to operate in these conditions? Will a rapid intervention team (RIT) be needed on site? This article will answer these and other questions pertaining to storm drain operations.

Hazards & Challenges
A rescue team may enter a storm drain to perform a recovery as mentioned above or to remove a trapped individual, such as a curious teenager or a public works employee who underestimated the hazards. But as with most rescue operations, there are inherent hazards and challenges that rescuers will encounter when working inside a storm drain system. If not properly prepared, rescue teams could easily become injured or in need of medical attention. Let’s take a closer look at some of the challenges you may face and how to handle them.

In a perfect world, a storm drain system would contain nothing but rainwater; however, we know that other, more hazardous things find their way into our systems. At times of low or no water flow, something as mundane as the off-gassing of organic material may create a toxic atmosphere.

Remember: 80% of confined-space fatalities are due to atmospheric hazards. Do not underestimate that hazard. Several electric PPV fans, with an appropriate length of ducting, placed at the entrance and at access intervals will help ensure proper air flow. You’ll also need multi-gas air monitors so you can monitor the air prior to ventilation, at each end and at the access points along the route.

Both access and egress may require rescuers to move through a pipe that’s 48 inches or smaller in diameter. Access to a storm drain system may be from either end or from a manhole at street level. In either case, if entrants pass a vertical access opening during their entry, the team must be prepared to do a vertical entry/extraction. Important: Vertical manhole ladders are often set back from the manhole access point, which makes it awkward to go from ladder to manhole or vice-versa, especially if you’re working in a class III harness and appropriate outer gear. A pre-rigged 4:1 haul system or cable winch on a tripod set up above the manhole will ensure safe passage up or down.

Prior to entry, all manhole covers should be removed to provide a shorter access point for your rapid intervention team (RIT) and to allow your entry team to exit before the end of the system. Tip: Heavy equipment may be needed to uncover some manholes.

Either end of the storm drain system may also have as much as 4 or 5 feet of standing water around it. Anticipate this problem by bringing portable pumps, which may also help divert incoming water.

A flash flood due to rainfall, incoming tide, a water emergency at street level or an increased snow melt could all lead to an engulfment situation. A simple “I’m stuck” problem can become terrifying if the water level rapidly increases in a small pipe and you’re unable to move. To divert water flow and reduce the chance of engulfment, use sand bags, plywood and or even a back hoe. As previously mentioned, water-removal pumps should be on site and a RIT prepared to deploy. Do not underestimate how quickly diverted water can build up; preplan its route of travel and where it will end up.

Entrapment & Other Hazards
Over time, corrugated pipe gets worn and cracked. Nasty fingers of steel may hang down, which can snag your tag line, clothing, air lines or harness straps. Once stuck, it may be difficult to untangle yourself. Tip: When you feel a tug in a confined area, don’t “be a guy” and continue to crawl forward. Try backing up a bit to free yourself. If that doesn’t work, tell your partner and outside team members immediately. It may take a few minutes to send assistance to you.

What else is in the system? Are animals living in it? When you surprise an animal in its living area, it may attack you. A raccoon or pissed-off opossum can cause serious damage. The eastern portion of our country and some of the southern states may also have snakes living in or traveling through their systems, so proceed with caution.

PPE & Thermal Protection
If it’s July in Arizona, the cool water in the system may be a welcome relief from the heat. But if you’re in the Pacific Northwest, you’ll quickly become chilled without appropriate thermal protection; the best may be a dry suit with attached socks or booties. Replace your duty boots with a pair of water-specific shoes or an old pair of running shoes. Depending on the air and water temperatures, you may want to wear a fleece liner underneath the dry suit. Both dry suits and wet suits can be protected by wearing coveralls over them. To keep your hands warm, wear neoprene gloves. On top of all of that, you’ll wear your class III harness. For lighting, use a helmet-mounted head lamp and a secondary light source as you would for any confined-space entry.

Respiratory Protection
Due to the length of the storm drain system, if you choose to wear a supplied air breathing apparatus system, you’ll need to exit every 150–300 feet, as air lines won’t run the entire length of the system (and the manufacturer limits you to no more than 300 feet). If entrants are going to exit every 150–300 feet, you’ll also need to pull the disconnected air line out of the system. This could become problematic as the air line or umbilicus could become snagged.

For entries that don’t have atmospheric issues upon initial reading, entrants can wear SCBAs with their facepieces donned, but without being on air. If their monitor goes into alarm, they can don their mask and exit as soon as possible.

Team members may be several hundred feet from the entry point so communication must be continuous and precise. Hardwired communications systems seem to be the most reliable means of communicating between users above and below grade, but you may decide that you don’t want to drag and retrieve a hardwire line through the system. If your entry team is using handheld radios, but doesn’t have waterproof versions, try putting the radios in dry bags made specifically for portable radios.

You may need multiple users to relay radio traffic to the entry group supervisor. Station someone at each entrance/exit and along the route of travel at the manholes. Using a simplex channel that bypasses a repeater will improve your communications. This is similar to how fire companies communicate when operating below grade in some subway systems.

Site Information
The size of the pipes, the distance between inlet and outlet and the distance between manhole access points are important elements to consider when creating a tactical plan. Contact the public works or water district responsible for the system to get the information you require. They can provide you with a site drawing or map that will help you plan your entry.

Emergency Action Plan
The RIT may not enter the space at the same location that the entry team initially entered. If an emergency occurs in which the RIT is needed, there may be closer access points using manholes and vertical ladders. This means that, ideally, the RIT should be mobile rather than stationary. Basing the RIT out of a vehicle will allow them to quickly deploy from the most appropriate access point. If the RIT uses supplied air breathing apparatus (SABA), the SABA will need to be carefully packed in the vehicle so that they can be deployed quickly and easily, and not be trapped in a rat’s nest of air lines.

Personnel Management
Like any technical rescue incident, an incident management system (IMS) must be in place early. If you’re given advanced notice of the entry, preplan who will fill key supervisory positions. Vests or helmet fronts will assist in keeping track of supervisor locations.

If the operation becomes extended, plan for your command post to become more than the back of an SUV. If you don’t have a regional mobile command post available, and there’s no indoor site nearby, consider borrowing a bus from the regional community transit system.

Training Needs
In the case of a storm drain system, training needs will include confined space and, depending on the depth and speed of the water, swiftwater training. Dive team members who will use SCBA or SABA will need to be trained on their use and be fit tested. Technical rescue team members will need to be briefed on the hazards associated with entering moving water. They may also require a briefing on evidence preservation.
Consider setting up your entry teams with a rescue tech and, in this scenario, a dive team member, if they’ve been trained on confined-space entries and the use of appropriate respiratory protection.

If making multiple entries from multiple locations simultaneously, you may need several tripods and haul systems, as well as ventilation equipment and air monitoring equipment. Make a detailed list of your needs and then determine what you have available. Factor in equipment failures and have replacement equipment on hand. Assign a rescue tech to manage the equipment, and be able to make repairs in the field as needed. After each use, inspect all equipment after it has been dried.

What Happened?
Back to the scenario at the beginning of this article: Twenty-five members of a fire-based county rescue team and a sheriff’s department dive team spent more than four hours in the rain searching two 1,750' sections of a storm drain system. A mobile RIT followed the progress as two teams worked in parallel systems. There were no injuries. The search came up negative.

Remember: The ability to preplan these types of difficult entries and a good IMS will make other, similarly unusual entries go much smoother.

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October 2017
Volume 12, Issue 10