By John Seamon JR, Captain Phillipston Fire
This past weekend the Phillipston Fire Department hosted the Massachusetts Fire Academy’s Trench Rescue Technician Level Course. The class went Thursday night 4-11PM, Friday 9-5, Saturday 9-430, and Sunday 9-4. The class was taught by MFA instructors who guided the students on the proper way of shoring up trench walls and three ways to extract a patient who was injured while working in a trench.
Thursday night’s class started with a slide show presentation, and then the students went into the apparatus bay area to go over the equipment which included low and high pressure air bags, air struts, wood struts, hardback panels, cribbing, saws, and how different dimensional lumber would be used.
On Friday morning a trench was dug 16’ long x 4’ wide x 7’ deep. This straight trench was secured by using 4x4’s, 4x6’s, and 6x6’ lumber, Initially Instructors wanted the students to work with lumber to properly secure the trench walls. Using wood, and cutting the required pieces took almost three hours. After lunch, round two started and this time the students were introduced to air struts and these air struts to support the trench walls. Air struts require the use of high pressure regulators and air hoses attached to a 45 minute 4500 PSI SCBA bottle.
Saturday morning began with a new 18’ x 5’ wide x 7’ deep trench. When digging the trench the MFA had the backhoe operator undermine one of the trench walls about 4’ long and 2’ in so the students could use whalers. Whalers are 6”x6”x12’ pieces of lumber, when lowered into the trench these are applied against the outside areas where the trench wall is not solid. Strong backs then have a solid mass to push against when air pressure is applied to the struts. Once the trench is secured the MFA instructor’s had the students work on one method of patient extraction using a ladder and stokes basket.
After lunch, students installed inside whalers, inside whalers are used to span the inside of the trench. When a trench collapses or the spoil pile collapses causing the victim to be covered by 2’ or more under the dirt you can add 2”x12’ lumber behind the whalers which provides the rescue to keep digging lower. When an additional 2’ foot of soil is removed the boards can be moved lower and the rescue teams can continue operation. After a 4’ foot of additional depth is reached, another set of air struts would need to be applied. Once the victim was uncovered, the MFA instructors taught the students how to extract a victim using ropes and weaving the stokes basket through the air struts until it was free to raise above the highest strut, then the extraction team walked the victim to the safe area.
On Sunday morning a “T” trench was dug, the “T” trench is difficult and considered a technician level trench. The reason is on a straight wall trench there are only two walls opposing trench walls to support (left and right). On a “T” trench there are three trenches that intersect and six trench walls that need to be shored. This requires the use strong backs, air struts, inside and outside whalers, and low pressure air bags. All three trench walls need to be installed with low pressure on the struts, and then increased pressure to 100 PSI simultaneously so one set of air struts does not collapse the other trench wall. Once the three walls were fully secured the group stopped for lunch. When training commenced again, the MFA instructors had the teams build an “A” frame out of ground ladders with a block and tackle pulley system to lift the patient out of the trench using a harness around the victim.
Chief Stevens, Captain Seamon, Lieutenant Stanley, and FF Mason attended the class with twelve other firefighters from across Massachusetts.