Gas Detection using Colorimetric Tubes

Detector Tubes

• A portable pump draws a known volume of air through a detector tube to measure the concentration of a substance.
• The color of the tube changes and is read on a scale printed on the tube.
• Types of detector tubes: Drager (L) and Gastec (R) colorimetric tubes.

Considerations for Detector Tubes

• Measurement accuracy
• Limits of detection
• Interferences
• Temperature/humidity
• Shelf life
• Time period for which the color stain is stable after sampling
• Readings should be compared to the appropriate short-term exposure limits, such as TLV-STEL and TLV-C.

Storage and Shelf Life of Tubes

• Tubes have a shelf life, with expiration dates printed on the box.
• Proper storage: avoid excessively low or high temperatures and direct sunlight.

Advantages of Detector Tubes

• Operation with one hand
• Low weight and simple operation

Understanding Toxic Chemicals

• Threshold limit values (TLVs) are airborne concentrations of substances to which most workers may be repeatedly exposed without adverse effect.
• One part per million (ppm) is a small concentration, equivalent to:
• 1 meter in 1,000 kilometers
• 1 milliliter per 1,000 liters of liquid
• 1 square centimeter in 100 square meters
• 1 cent in 10,000 dollars

Threshold Limit Values (TLVs)

• Threshold Limit Value – Time Weighted Average (TLV-TWA) is the time-weighted average concentration for a normal eight-hour workday and a 40-hour workweek.
• TLV-TWA is the concentration to which nearly all workers may be repeatedly exposed without adverse health effects.

First Response to Hazardous Materials

• Rescue members should be competent in site-specific response procedures.
• Resources for rescuers:
• The Emergency Response Guidebook for Incidents Involving Hazardous Materials
• Material Safety Data Sheets (MSDS) or Information Sheets
• CANUTEC (Canadian Transport Emergency Centre) and WISER (Wireless Information System for Emergency Responders)
• On-site expertise

Physical/Emotional Stress in Critical Incidents

• A critical incident is an event that is outside the range of usual human experience and is psychologically traumatic to the person.
• Critical incidents may produce a wide range of stress reactions, which can appear immediately or within a few days of the event.
• Stress reactions can occur in four categories:
• Cognitive (thinking)
• Physical (body)
• Emotional (feelings)
• Behavioural (actions)
• The more reactions experienced, the greater the impact on the individual.

Knots, Bends, and Hitches

• A knot must be safe for its intended use, strong enough for its role, easy to tie and untie, and not affect the strength of the system beyond the acceptable safety factor.
• Types of knots:
  • Overhand Knot: basic safety knot
  • Figure Eight: basic safety knot
  • Bowline: creates a loop that will not jam, slip, or fall
  • Bowline on a Bight: creates a double loop
  • Figure of Eight on a Bight: creates a loop that forms the main point of attachment
  • Double Figure of Eight: creates two loops that form the main point of attachment
  • Butterfly Knot: creates a loop in the standing part of the rope that provides an attachment point for multidirectional use
• Bends:
  • Double Sheetbend: used for tying two ropes of unequal size together
  • Double Fisherman's: used to join two ropes of equal diameter
  • Ring Bend: for connecting webbing to webbing
  • Figure of Eight Bend: used to tie two rope ends together end-to-end, in order to extend them
• Hitches:
  • Clove Hitch: used for securing a rope to a pole or post
  • Timber Hitch: used to hoist or drag timber or pipes
  • Munter Hitch: used for single-person belaying in low-angle situations
  • Prusik Friction Hitch: used to attach a larger diameter rope without knotting the rope
  • Tensionless Hitch: used for anchoring a rope
  • Two Round Turns with Two Half Hitches: used to secure rope to a post or pipe
  • Cat's Paw: used to secure rope to hooks and rings

Harnesses

• Types of harnesses:
  • Butterfly Harness: used when only a rope is available to safely lower or raise a casualty
  • Webbing Harness (Upright): used for an upright person who requires an easy, quickly made full-body harness
  • Webbing Harness: used for casualties who are either unconscious or supine and require a rapid rescue
• Key points for using harnesses:
  • Ensure the harness is comfortable and snug
  • Avoid placing knots in a way that creates pressure points on the wearer's body
  • Use padding between the rope and the wearer's body where there are points of pressure
  • Secure the eye to the loops with two half hitches to prevent slipping and tightening of the knot on the wearer's body

Blanketing a Stretcher

• Objectives:
  • Provide the casualty with warmth for shock or environmental conditions
  • Comfort the casualty by ensuring there is nothing that can cause pressure points on the casualty's body
  • Allow a rescuer to quickly access the vital signs and injuries of the casualty
  • Keep the blankets from being loose and potentially getting into rigging systems
• Procedure:
  1. Lay blankets as shown, avoiding bumps that could cause pressure points
  2. Load casualty in, leaving a space at least 4” from head to rail if possible
  3. Wrap around legs, keeping loose at feet if a rope tie-in is to be used
  4. Finish by pulling the upper body blanket over and tucking it in

Basket Stretcher Tie-In

• Objectives:
  • Secure the casualty sufficiently to reduce aggravation of injuries during transport
  • Prevent the casualty from sliding around or slipping out of the basket
  • Ensure the casualty is well-secured while moving from one height to another
  • Prevent the casualty from moving within the basket when it needs to be moved from partial tipping to a full vertical position
  • Fully secure the casualty in the basket when the rescuer cannot accompany them for the duration of a rescue
• Herringbone Tie-In procedure:
  1. Thread half of the tie-in web or rope through the bottom section of the stretcher, below the lowest cross member
  2. If using a rope, lay the center of the tie-in on top of the stretcher rail, wrap around the feet with a clove hitch, and pull the loop between the feet over the clove hitch
  3. If using webbing, form bights on each side of the stretcher, pull one through the stretcher, and push through the 1st loop at the feet