Palm Beach County Fire Rescue SOG 420-05 Ventilation PDF

Palm Beach County Fire Rescue Standard Operating Guideline SOG 420-05 Ventilation Issue Date:05/21/20...

Palm Beach County Fire Rescue Standard Operating Guideline SOG 420-05 Ventilation Issue Date:05/21/2018 Effective Date:06/21/2018 PURPOSE: To provide guidelines that enable Fire Rescue personnel to make sound decisions regarding the use of mechanical or natural ventilation to remove an IDLH atmosphere from a specified area. This shall be accomplished horizontally or vertically, utilizing positive or negative pressure techniques specific to conditions. AUTHORITY:  Fire Rescue Administrator SCOPE: This standard guideline shall apply to all Emergency Operations personnel. ATTACHMENTS: Attachment A: Super Vac P164 Series Fan Manual Attachment B: RAMFAN Manual PROCEDURE: 1. General Information a. All Ventilation efforts shall support the increased tenability and survivability of civilians and firefighters. b. Ventilation MUST be coordinated with Fire Attack operations. c. Specialized situations (i.e., confined space, high rise fires, etc…) require specific ventilation methods that are NOT covered by this SOG. 2. Basics of Ventilation a. Three basic principles apply to ventilation: i. Vent for Life Safety 1. Ventilation helps to clear a contaminated atmosphere from a structure, which gives occupants a better chance to survive. ii. Vent for Fire Containment 1. Releasing a contaminated atmosphere to the exterior prevents it from spreading throughout the interior of a structure. iii. Vent for Property Conservation 1. Ventilation can significantly limit property damage. iv. The Incident Commander or is responsible for the determining the ventilation: 1. Type (Vertical or Horizontal) 2. Method (Natural or Mechanical) SOG 420-05 Ventilation Page 1 of 4  b. Type i. Vertical Ventilation 1. Vertical ventilation takes advantage of the natural tendency of heat to rise. 2. Vertical Ventilation involves openings in roofs or floors so that a contaminated atmosphere can escape from the structure in a vertical direction. 3. Pathways for vertical ventilation can include stairwells, exhaust vents, and roof openings such as skylights or scuttles. Additional openings can be created by cutting a hold in the roof or floor. ii. Horizontal Ventilation 1. Horizontal ventilation can be used in any of the basic ventilation situations. 2. Horizontal ventilation utilizes the doors and windows on the same level as the fire, as well as any other horizontal openings that are available. 3. Horizontal ventilation is usually safer and faster than vertical ventilation. c. Method i. Natural Ventilation 1. Natural ventilation depends on convection currents, wind, and other natural air movements to allow a contaminated atmosphere to flow out of a structure. 2. Wind speed and direction play an important role in natural ventilation. ii. Mechanical Ventilation 1. Mechanical ventilation uses fans or other powered equipment to exhaust a contaminated atmosphere and/or introduce clean air. 2. There are three different methods of mechanical ventilation: a. Negative pressure b. Positive pressure c. Hydraulic ventilation 3. Negative pressure a. Negative pressure ventilation uses fans to exhaust a contaminated atmosphere from a structure. 4. Positive pressure a. Positive pressure ventilation uses fans to introduce clean air into a structure and push the contaminated atmosphere out. b. Once clean air is introduced with positive pressure into the building, it follows the path of least resistance, and travels towards the exhaust opening. 5. Hydraulic ventilation a. Hydraulic ventilation moves air by using fog or broken-pattern fire streams to create a pressure differential behind and in front of the nozzle. SOG 420-05 Ventilation Page 2 of 4  6. HVAC systems a. Some buildings have HVAC systems or specifically designated smoke management system to provide mechanical ventilation. These systems can be positive or negative pressure systems. 3. Vertical Ventilation a. Due to resource availability, building construction and firefighter risks associated with vertical ventilation, alternative ventilation options should be considered. b. Refer to SOG 420-06 Roof Operations for Vertical Ventilation. 4. Horizontal Ventilation a. Negative Pressure Ventilation i. Fire Rescue utilizes an electric fan, Super Vac P164 Series, for negative pressure ventilation. ii. The electric fan should be placed at a high point in a door or window on the leeward side. b. Positive Pressure Ventilation (PPV) i. Fire Rescue utilizes a high-volume velocity fan, RAMFAN, for positive pressure ventilation. ii. The high-volume velocity fan is capable of providing up to 13,000 cubic feet per minute (cfm) of air volume. iii. The high-volume velocity fan should be placed: 1. On the windward side. 2. 4-10 feet outside the ventilation opening (so that the cone of air from the fan completely covers the opening). iv. When selecting an exhaust opening for PPV, it should be: 1. On the leeward side. 2. Close to the fire. 3. 1-2 times the size of the ventilation opening. v. Smaller exhaust opening sizes may be used when cooler gases with less energy are being ventilated. vi. To expedite the process, doors to rooms may be closed. 5. When NOT to use PPV a. PPV should NOT be used when: i. The seat of fire is NOT located. ii. The fire is NOT under control. iii. There are pre-flashover conditions. The 5 impending signs of pre-flashover conditions are: 1. High heat 2. Thick, turbulent, black smoke 3. Roll-over 4. Uncontrolled fire in the interior 5. Auto-ignition (a.k.a. vent-point ignition) of smoke at exhaust openings. iv. There may be hidden fire in void spaces (i.e., chases, floors, walls, attics, etc…) v. Three is no exhaust openings vi. There are strong winds against the exhaust opening. SOG 420-05 Ventilation Page 3 of 4 Supersession History 1. SOG #1725, issued 03/01/2006 2. SOG #1725, issued 08/01/2006 3. SOG 420-05, clerical 04/01/2018 4. SOG 420-05, issued 05/21/2018 SOG 420-05 Ventilation Page 4 of 4