Super Vac
The Ventilation Specialist

Super Vacuum Manufacturing makes no warranty implied or stated about the specific use of any of the applications in this manual. Organizations using this manual are strongly encouraged to practice ventilation theories under controlled conditions. Everyone using ventilation products must thoroughly understand the SAFETY PRECAUTIONS in this manual.

Ventilation
Throughout this manual, ventilation is discussed in relation to smoke. Smoke is a convenient media to use in air movement because of its visibility. However, the same principles apply to many toxic fumes, paint, welding fumes, vehicle exhaust, dust, and other airborne contamination.

The replacement of the products of combustion, heat and fire gases, with fresh air is VENTILATION. Ventilation on the fire ground is essential to the overall objective in that it enables firefighters to complete their mission of RESCUE and EXTINGUISHMENT faster and safer. Through a coordinated attack that included the ventilation of the fire building, firefighters will work in an environment that is more tenable for the firefighters themselves, and any trapped occupants located in the building. Ventilation reduces the conditions of back draft and flash over in addition to increasing visibility for other fire ground operations.

Fire ground commanders are now realizing the benefits of ventilation through the efforts of many years of research by manufacturers, fire departments, insurance companies, and through their own experiences. Research has shown that the sooner the ventilation process occurs in the overall fire ground plan, the greater the reduction in property damage, and the greater the reduction in manpower and equipment needs. As fuels have changed over the past several years, the ventilation objective has become more and more important. With this change in fuels, fire gases have become considerably toxic. This increase in the toxic content of fire gases has had a dramatic effect on the way we attack fires.

Ventilation can be achieved through "natural means" or through "mechanical means". Natural ventilation includes opening widows and allowing the wind to provide fresh air to the fire building environments. It also includes the self-ventilation of the fire when it burns through the roof, thereby allowing the trapped fire gases to exhaust through the roof opening. Mechanical ventilation includes using HVAC systems built into buildings, using fog streams out of widows to create air movement, and negative or positive pressure ventilation through the use of specialized fire service fans. This manual will concentrate on the use of specialized fire service fans to create positive and negative pressure ventilation.

Super Vac has been providing special fire service fans to the fire service since 1926. Since that time, Super Vac has been involved in every development in fire service ventilation practices. Our research and development people receive hundreds of inquiries and suggestions throughout the year. Super Vac works with many fire service training organizations such as the International Fire Service Training Association (IFSTA) and the International Society of Fire Service Instructors (ISFSI) to improve the technologies available to fire departments. This manual is an example of our commitment to the fire service personnel of the world.Ventilation Theory

Why Ventilate?
During the incipient state of fire (the early state), the oxygen content of the environment is not changed dramatically. The fire is however adding carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), water vapor, and other gases. During this phase of fire, flame temperatures reach 1000 degrees, while the temperature in the room may only change a few degrees. The products of combustion - CO2, SO2, CO, and H20, all have oxygen in their makeup (O2 or O2). This means that oxygen is being used during the combustion process; if a continuous supply of oxygen is not available, the fire will go out (smoldering phase). The second phase of fire is the free burning phase. This phase can not occur without the continued supply of oxygen. As air is introduced to the base of the flame, heat and fire gases will rise until stopped by the ceiling or other building part, or until they cool to equal ambient temperature. These super heated gases may reach temperatures between 1200 and 1500 degrees Fahrenheit. The inhalation of these fire gases can cause instant death.

In the smoldering phase, the third phase, burning is reduced due to the lack of oxygen. The greatest smoke generation occurs during this phase. So much smoke may be generated that it pressurizes the structure with smoke. Smoke may be seen from the exterior of the building. Smoke and fire gases may still be above 1000 degrees Fahrenheit.

During a fire, different areas involved in fire will or may be at different stages. Smoke and hot fire gases kill more people and cause more damage than flames. In addition, these products of combustion make it more difficult to perform rescue and extinguishment operations because of low visibility and the physical stress placed on personnel.

Smoke and Fire Gases Smoke is the mixture of the products of combustion with air and dust. These products include, but are not limited to, carbon, organic acids, aldehydes and tar. Many products of combustion are heavier than air, however in the heated environment of the fire, they expand and rise. As the room cools, these lethal fire gases become denser and fall to the floor level. For this reason, ventilation and the use of breathing apparatus must continue during the overhaul phase of operations. Breathing apparatus use does not preclude the use of ventilation techniques; many products of combustion may be absorbed through the skin, especially in the areas of the firefighter's neck and wrists. Firefighters assigned to busy companies have an additional risk in that fire gases are cumulative in the body. Conditions that affect the level of danger include:

• The level of oxygen in the area
• The temperature of the fire gases
• The products involved in the fire
• The duration of exposure
• The physical condition of the firefighter

Ventilation can effect all but the physical condition of the firefighter, thereby reducing the risk considerably. Firefighters exposed to the products of the combustion should be given 100% oxygen therapy. Again, ventilation reduces the risk. The long term effects of exposure to fire gases are still not known. However, we do know that carcinogens are produced during the combustion of some products. In addition to the carcinogens, immunosuppressants are produced during fires. These suppressants inhibit the immune system of the body from protecting itself.

Flashover
Flashover occurs when the contents of a room or area reach their ignition temperature almost simultaneously. Flashover may appear as a wave because as one space ignites, the increase in temperature causes the next space to reach its ignition temperature. Ventilation procedures can reduce the flashover risk by reducing the temperature in the entire area.

Backdraft
A backdraft situation exists when the environment should be in a flashover, however there is not sufficient enough oxygen to support combustion. When oxygen is introduced into this environment, an explosion occurs as the fire spreads.

Ventilation is required in this case, however it is important to understand the entire ventilation process and carry it out carefully under backdraft situations. Some signs of backdraft are:

• Puffing smoke outside the building or area
• Dense black smoke turning grey to yellow
• Little or no flame
• Smoke stained windows
• Smoke leaving then re-entering the building
• Excessive heat with no visible fire

Protection lines for the ventilation crew should not be used for firefighting lines unless specifically directed to do so by the command post. Attack crews could be in jeopardy if ventilation crews fight the fire from the wrong vantage point. The tactical objective of the ventilation crew will determine where and how ventilation is done. For rescue, generally, positive pressure is needed between the trapped and the fire and between the trapped and the exit. This may or may not be easily identifiable. Once the rescue mission is completed, ventilation equipment may need to be repositioned for attack operations or for overhaul operations.

During attack operations, positive pressure is needed between attack crews and the fire with the exhaust opening on the opposite side of the attack.

Whenever possible, ventilation crews should take advantage of smoke and fire gases natural tendency to rise. While a potentially dangerous operation, some situations call for firefighters to make their way to the roof and cut it open. This will release super heated fire gases, smoke, and sometimes fire through the hole. A protection line is required. Never put the protection line on or in a vent hole unless it is for the direct protection of the ventilation crew. Once a ventilation hole has been cut, retreat to the ground for reassignment. This may be to set up positive pressure within the building to take advantage of the vent hole in the roof.

On a smaller scale, firefighters can take advantage of smokes tendency to rise by placing fans at the highest point in the exhaust opening. This opening may be a window or a door, or it may be an opening created during the ventilation process. During positive pressure operations, ventilate the bottom floor first and work your way to the top.

Mechanical Ventilation
Mechanical ventilation is required whenever natural ventilation is even partially unsatisfactory. Mechanical ventilation procedures should begin immediately to assist in rescue or attack operation, or when it is felt that the natural process is too slow, causing excessive damage to property. Mechanical ventilation should be used to maintain egress routes for occupants and firefighters. Mechanical ventilation should be used to augment natural ventilation, or when smoke is below grade. Generally speaking, when applied correctly, you can not over ventilate. More often than not, the fire service under ventilates during fire operations due to poor training, severe manpower limitation, poor equipment, or a misunderstanding of the value of ventilation procedures. Usually it is a combination of the above.

Mechanical ventilation is possible by creating positive and negative areas and directing air currents with the principle that air will travel from a positive or neutral area of pressure to an area of negative pressure. Using mechanical force, we can create negative or positive pressure on the fire ground one of two ways.

1. Specially designed smoke ventilators
2. Fog streams

• Use large quantities of water for non-attack operations.
• Must be continuously manned
• Often can only be used directly to outside of building
• Create additional water damage
• Require continuous use of pump

Churning
A division must be maintained when creating mechanical ventilation between the positive side of the equipment and the negative/neutral side. If a separation is not made, air will flow from the positive side back around to the negative side making the operation less effective (churning).

Ventilation Decision Tree

Requirements for Effective Mechanical ventilation

1. Use good, reliable, portable equipment.
2. Be sure to use a large enough ejector or enough ejectors to perform the necessary task.
3. Provide proper training in technique to acquire maximum benefit from the equipment.
4. Practice good pre-fire planning that includes ventilation options.
5. Know proper placement of equipment under any condition.
6. Plan so that equipment, training, methods, and tactics will work to accomplish the desired results with no wasted time.
7. Take advantage of smoke's natural tendency to rise.
8. Initiate ventilation as soon as tactically possible.
9. Include ventilation as part of standard operating procedures (S.O.P.).
10. During negative ventilation operations place fan as close to smoke source as possible.
11. Use combinations of fans to achieve the best performance, either combinations of positive and negative pressure, or stacked fans for additional volume.
12. Use prevailing winds as much as possible.
13. Prevent "churning air" by maintaining a ‘wall' between the positive and negative sides of the fan.
14. Keep air paths clear. Take advantage of air's natural tendency to follow the path of least resistance.
15. Remove screens and other obstacles. Maintain the closure integrity so the window or door can be closed.
16. Coordinate the ventilation operation, rescue and attack operations.
17. Maintain control of replacement air and/or exhaust openings.
18. When ventilating more than one floor, start at the bottom and work toward the top.
19. Never use gasoline powered fans in smoke atmospheres.
20. Use only fans with explosion proof motors inside questionable atmospheres.
21. During positive pressure operations clear one room at a time.
22. Never place hoselines into ventilation openings.
23. Use safe handling practices when carrying fans.
24. Make sure that created drafts do not close doors or windows.
25. Do not use any fan without protective guards.
26. Ground all electrical equipment.
27. Explain how and why ventilation works to the media.
28. Maintain ventilation operations during overhaul.
29. Use fans in conjunction with HVAC system operation.
30. Pressurize first, then open up, maintaining control of air movement.

Using Combinations of Fans
Using more than one fan increases air input and speeds up the ventilation operation. This can be multiple fans at a single inlet, using more than one outlet, or using fans in a stack. Combinations can also include both positive and negative pressure operations. When using gas fans, remember that it is not recommended that gasoline fans be used indoors. Use electric fans for indoor or outdoor use.

1. Multiple fans at inlet, parallel, with series fan changing direction of air current at fire room.
2. Multiple fans at inlet, stacked, with series fan changing direction of air current at fire room.
3. Multiple fans at inlet, series. One fan inside cone of second fan.

   When using combinations of fans it is very important to allow sufficient openings for air to flow to a fan in negative pressure operation and from a fan used in positive pressure operation. If openings are too small the efficiency of the fan will be reduced.

4. Multiple fans at inlet, stacked, with series fan in line.
5. Multiple fans at inlet, parallel, with negative pressure fan at outlet.
6. Multiple fans, multiple inlets.

If a large fan is producing 12,000 CFM and the opening is only 60% of the cone, then you only have 7,200 CFM going in through the door opening.

The design of the stack fan is such that the door is sealed top to bottom with the units closer to the door. Two Super Vac fans at 6,000 CFM each will put 12,000 CFM through opening and seal doorway.

The saddle and legs will allow up to 3 electric units to be stacked and used in either positive or negative pressure situations.

Using Wind Direction
One of the most important requirements of successful ventilation is knowing how to use the prevailing wind to your advantage. Once the wind speed and direction is determined, the ventilation team can begin their set-up using either positive or negative pressure ventilation to best clear the smoke.

Negative Pressure Ventilation

Negative pressure is when smoke is moved through the fan from the negative side first. It has been the industry standard for many years, and remains the most versatile tool in ventilation. It is the only recommended method of ventilation in situations like hospital and nursing home uses, cave-ins, and interior rooms. Electric fans do the majority of negative pressure work since they are not affected by the ambient, do not produce CO, and can be used in any position.

Advantages of Negative Pressure Ventilation using Electric Smoke Ejectors

1. Reduces property damage.
2. Increases visibility and safety.
3. Can maintain primary and secondary egress routes.
4. Reduces overhaul time.
5. Can utilize electric fans.
6. Can utilize explosion proof motors.
7. Does not require a great deal of coordination with other operations.
8. Is not upset easily.
9. Requires little manning.
10. Can be used in conjunction with flexible duct equipment.
11. Works well in small area situations such as a single room.
12. Works well in the removal of heavier than air gases.
13. Works well from aerial equipment from the exterior of high rise rooms.
14. Works when opening integrity is not maintained.
15. Electric smoke ejectors do not produce CO.
16. Can be used in cave-ins.
17. Can be used to cool firefighters in staging areas.

Window Placements
There are as many ways to utilize the Super Vac unit in window locations as there are types of windows. However, two principal kinds of windows are encountered, the double-hung window and the casement-type window.

Double-Hung Windows

1. Raise lower window.
2. Place Super Vac unit on window sill and pull window down onto handles.
3. Secure both hooks of the Super Vac hanger unit into bottom rail of the window.
4. Wrap cable of hooks around handle to obtain length which will hold smoke ejector securely on lower rail of window. Properly installed, the Super Vac unit performs unattended and ejects smoke at maximum efficiency. NOTE: Be sure the unit is correctly placed. To direct smoke, fan blade must be on the inside forcing air over motor to outside. Reverse the position to pull in fresh air.

Casement Windows

1. Roll window open and place one hanger hook over top window hinge.
2. Fasten the second hook into the mullion of the window to steady the unit.
3. Rest unit on metal edge of window to prevent damage. This placement is of tremendous value in venting the common mattress fire or similar one-room fires.

Negative Pressure Door Placement
With the fan on the smoke side of the doorway, place a fan or fans far enough away from the doorway so as to cover the doorway with a cone of air coming from the fans. This will create a venturi effect with the air going out the door, increasing the fans effectiveness by as much as 100%. Stacking fans will increase volume greatly, reducing ventilation time and increasing ventilation effectiveness. For oversized doors, place fans side by side to overlap their cones of air. An alternate method of using two fans in a doorway is to place one fan on the door, and a second fan away on the floor.

The following guidelines should be used only as an aid in determining the correct placement of Super Vacs based on the sizes of the door and the ejector.

• 16" Super Vac exhausting through a 36" door should be positioned 6' to 8' from opening.
• 20" Super Vac exhausting through a 48" door should be positioned 8' to 10' from opening.
• 24" Super Vac exhausting through a 48" to 60" door should be positioned 6' to 10' from opening.

WRONG: If fan is placed too close to the opening re-circulation possibilities exist.

WRONG: Too far from opening

In large door openings, place ejector slightly farther back or use multiple ejectors.

Positioned in this manner the ejector not only moves the air passing through the propeller, but also draws air into the air stream on the discharge side. Efficiency increases by 20 to 100% of rated capacity. Actual increase varies according to the size of the smoke ejector, the size of the door opening providing replacement or make up air.

The smaller the smoke ejector, the lower the increase in capacity, and vice versa. This is mainly because of the difference in velocity and the concentrated reach of the air stream. By positioning either a 16" or a 24" Super Vac 8 to 10 feet inside a door measuring 30" x 84", the volume of air exhausted will increase about the same for either ejector (30 to 40%).

CORRECT: TYPICAL PLACEMENT FOR EFFICIENT VENTURI EFFECT. Air inlet approximately 2 times air outlet.

Working with Negative Pressure Ventilation
Shown below are some of the many situations requiring the use of negative pressure ventilation.

• VENTING VAULTS, CLOSETS, OR CLOSED ROOMS
• ATTIC
• EXHAUSTING INTERNAL ROOMS WITHOUT OUTSIDE ACCESS

Positive Pressure Ventilation
Positive pressure ventilation is when fresh air is introduced through a fan into an area to increase the pressure in that area. When the pressure is increased, the air will move to an area of lower pressure. This follows the law that air will always follow the path of least resistance.

Firefighters can take advantage of the positive pressure laws in the area of smoke removal. By pressurizing a structure, and by using the selective process of opening and closing doors and windows, firefighters can direct the movement of smoke and fire gases faster than ever before. Not only does this process evacuate smoke and fire gases faster, it works on a volume of air system rather than a velocity of air system. This means that air currents are not as likely to cause damage. Because positive pressure ventilation is initiated from outside the structure, firefighters can implement ventilation operations immediately, without entering the hostile environment. As with all ventilation practices, firefighters performing ventilation should know where the fire is before they begin, as the ventilation process has the potential of moving fire and fire gases. Generally speaking, positive pressure should be initiated between firefighters and the fire, or between the fire and trapped occupants. The exhaust port should be on the opposite side from the firefighters or the occupants. Pressurization should occur after opening any exhaust port.

Advantages of Positive Pressure Ventilation

1. Reduces property damage.
2. Increases visibility and safety.
3. Can maintain primary and secondary egress routes.
4. Reduces overhaul time.
5. Can utilize electric or gasoline powered fans.
6. Does not require explosion proof motors.
7. Can be initiated from the exterior of the building.
8. Is effective on all structures when doors and windows are maintained.
9. Does not require smoke and fire gases to pass through the fan.
10. Is quicker than negative ventilation.
11. Keeps doorway clear of equipment.
12. Air velocity within building is reduced.
13. Equipment cleaning time is reduced.
14. Works well in large areas.

Stacking fans will increase volume greatly, reducing ventilation time and increasing ventilation effectiveness. For oversized doors, place fans side by side to overlap their cones of air. An alternate method of using two fans in a doorway is to place one fan in the door, and a second fan away from the door as to cover it with a cone of air.

In large door openings, place ejector slightly farther back or use multiple ejectors.

Positioned in this manner the ejector not only moves the air passing through the propeller, but also draws air into the air stream on the discharge side. Efficiency increases by 20 to 100% of rated capacity. Actual increase varies according to the size of the smoke ejector, the size of the door opening, and the size of the exhaust opening.

The smaller the smoke ejector, the lower the increase in capacity, and vice versa. This is mainly because of the difference in velocity and the concentrated reach of the air stream. By positioning either a 16" or a 24" Super Vac 8 to 10 feet inside a door measuring 30" x 84", the volume of air exhausted will increase about the same for either ejector (30 to 40%).

Positive Pressure Ventilation

Fan Placement
Following are guidelines as to the placement of fans for positive pressure applications. As with all such guidelines, one should follow these based on practice and experience.

The design of the stack fan is such that the door is sealed top to bottom with the units closer to the door.

The design of the saddle stack is such that all the air seals the door.

Use of Doors
Because fans are not located directly in the doorway for positive pressure operations, the ingress/egress route is not blocked by the fan. Because fans are not in the doorway, firefighters entering the building should be aware not to stand in the doorway as that will block the incoming air. Streamers can be hung in the doorway to indicate that it is a positive pressure ventilation inlet.

When using a garage door, open it only partway. Then using two fans, seal the doorway with the cones of air.

Working with Positive Pressure
All ventilation operations should be under the direction of the incident commander. This can be direct supervision, through a company officer such as a truck company officer, or through a ventilation section leader. Ventilation operations are as critical to the overall operation as are other operations. If the ventilation operation is neglected, the overall operation suffers.

Once a crew has been assigned to perform the ventilation operation, they must identity the location of the fire and the mission of the team. For example, if there is a backdraft condition, the crew should open up above the fire to exhaust super heated fire gases and products of combustion. If a rescue is to be made, the crew needs to place a positive pressure zone between the trapped persons and the fire, and a positive pressure zone between the rescue crew and the fire. When making a direct attack, the ventilation crew needs to place a pressure zone between the attack crew and the fire, then open up on the opposite side of the attack crew. Ideally, the attack should progress from the uninvolved area to the involved space.

To initiate positive pressure operations, either gas powered or electric powered fans may be used. Generally speaking, a larger fan will produce faster results, however always compare fans by their rated output, not by their size in inches.

Because positive pressure requires the select opening and closing of air exit points, care should be taken not to destroy the integrity of window and doors so that they are capable of being opened and closed to change the direction of air flow. This is contrary to many departments standard practice and will require new awareness and training. Also, firefighters using several doors as ingress and egress routes can reduce the effectiveness of the ventilation effort, again, training, and coordination is important.

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