Archive for May, 2013

Coming and going as a little kid, I frequently would forget to close the door to the house and my mother would say; close the door! Were you born in a barn? What does this have to do with firefighting operations? As it turns out, it has significant impact!

Research conducted by Underwriters Laboratories (UL), National Institute of Standards and Technology (NIST), and the Fire Department of the City of New York (FDNY) points to the importance of close coordination of tactical ventilation (including opening a door to gain access) and fire attack. While doors are not ordinarily considered a firefighting tool, this post examines door control as an essential element in firefighting operations.

The Fire Environment-A Quick Review

Modern homes have a high fire load (both in mass and heat of combustion of common building contents), are better insulated and more energy efficient, and are larger and have large open, undivided living spaces.

These conditions often result in rapid fire development and transition from a growth stage, fuel controlled burning regime to decay stage, ventilation controlled burning regime prior to the arrival of the fire department. Increased ventilation (without concurrent fire control) will result in increased heat release rate, returning the fire to the growth stage and rapid transition through flashover to a fully developed stage of fire development.

A number of factors influence the speed with which heat release rate accelerates when the air supplied to a ventilation controlled fire increases. These include building and compartment size and geometry, thermal conditions, and size and location of the ventilation openings.

• In general, fires in smaller compartments will react more quickly, but compartmentation and complex geometry will slow air movement from the inlet to the fire, and resulting increase in HRR.
• Introduction of air close to the fire will influence HRR more quickly than air introduced at a distance.
• Exhaust openings that are above the fire (horizontal or vertical) will increase HRR more quickly and to a greater extent than those at the same level (but may be more effective in improving conditions when fire control is established)
• Larger openings (or multiple smaller openings) will increase HRR to a greater extent and more quickly than smaller (or fewer) openings.

Conditions on Arrival

A critical element of size-up is identification of the current ventilation profile of the building. Remember that ventilation (exchange of the atmosphere inside the building and that outside the building) is always going on to one extent or another. Assessment of the ventilation profile is based on the Building, Smoke and Air Track elements of B-SAHF (Building, Smoke, Air Track, Heat, and Flame) Fire Behavior Indicators (FBI). Starting with Building factors, consider the nature of current ventilation openings:

• No significant ventilation openings (normal building leakage only)
• One or more doors may be open
• One or more windows may be open
• Some combination of door(s) and window(s) may be open

In addition to the ventilation openings, it is important to consider if they are exhaust openings, inlets, both exhaust and inlet, and what is visible; flames or smoke:

• Nothing showing (remember that this means nothing, the fire may be ventilation controlled and in the decay stage, but interior temperatures may be above 425^o C (800^o F) even when little or nothing is showing from the exterior.
• Smoke showing from ventilation openings (consider the direction of the air track at each opening, in, out, bi-directional, or pulsing)
• Smoke and flames showing from ventilation openings (as with smoke, consider the direction of the air track)

Structural Firefighting is Simple

OK this is a bit of an overstatement (actually more than a bit). Generally, there are only two things that firefighters can do to influence fire behavior; change the ventilation or absorb the energy being released by the fire. Read each of the following three scenarios and consider the questions posed. While examining door control, this anti-ventilation tactic is not used alone so there are a few questions that address fire control tactics (which will be the subject of a subsequent post).

Scenario 1: The first arriving company arrives to find a small volume of smoke showing from around windows and doors and from the eaves on Side Alpha with low velocity, no air inlet is obvious. Performing a 360^o reconnaissance, the officer observes similar smoke and air track indicators on other sides of the building and that all doors and windows are closed. Several windows on Side Alpha (Alpha Bravo Corner) are darkened with condensed pyrolysis products and the home appears to have smoke throughout (smoke logged).

1. How do you think the fire will develop between arrival and initiation of offensive fire attack (assuming that adequate resources are on-scene for offensive operations) assuming no change in ventilation prior to fire attack.
2. How would opening the front door prior to having a charged line at the doorway on Side Alpha impact fire development?
3. How would horizontal ventilation of the fire compartment (Alpha/Bravo Corner) impact fire development if performed as soon as the hoseline is deployed to the (still closed) doorway on Side Alpha?
4. What would be the impact on fire behavior if the engine company advanced the first hoseline to the windows; took the glass and applied water to the burning fuel inside the fire compartment prior to making entry through the door? How might this change if offensive fire attack was delayed (e.g., insufficient staffing for offensive operations)?
5. How would opening the front door and horizontal ventilation of the fire compartment (Alpha/Bravo Corner) impact fire development if performed as soon as the hoseline is deployed to the doorway on Side Alpha?
6. Assuming that sufficient resources are on-scene to permit an offensive attack, when should the entry point be opened? Assuming that the door is unlocked, how should this task be approached?
7. Once the hoseline is deployed into the building through the door on Side Alpha for offensive fire attack, should the door remain fully open or closed to the greatest extent possible? Why?
8. Assuming that this is a contents fire and horizontal ventilation will be appropriate, when and where should it be performed (describe the flow path from inlet to exhaust)?

Scenario 2: The first arriving company arrives to find smoke showing with moderate velocity and a bi-directional air track (smoke out the top and air in the bottom) from an open door on Side Alpha. A moderate volume of smoke is also pushing from around windows and from the eaves on Side Alpha. Several windows on Side Alpha (Alpha Bravo Corner) are darkened with condensed pyrolysis products and a glow is visible inside in the room behind these windows. Performing a 360^o reconnaissance, the officer observes similar smoke and air track indicators on other sides of the building and that all doors and windows with the exception of the door on Side Alpha are closed. Returning to Side Alpha, the officer observes that the velocity of smoke from the open door has increased and flames at the interface between the smoke and air as it exits the doorway. The home appears to have smoke throughout (smoke logged).

1. How do you think the fire will develop between arrival and initiation of offensive fire attack (assuming that adequate resources are on-scene for offensive operations) assuming no change in ventilation prior to fire attack.
2. How would the officer closing the front door prior to having a charged line at the doorway on Side Alpha (e.g., when performing the 360) impact fire development?
3. Assuming that sufficient resources are on-scene to permit an offensive attack and the door was closed during the 360, when should the entry point be opened? How should this task be approached?
4. How would horizontal ventilation of the fire compartment (Alpha/Bravo Corner) impact fire development if performed as soon as the hoseline is deployed to the open doorway on Side Alpha?
5. Once the hoseline is deployed into the building through the door on Side Alpha for offensive fire attack, should the door remain fully open or closed to the greatest extent possible? Why?
6. Assuming that this is a contents fire and horizontal ventilation will be appropriate, when and where should it be performed (describe the flow path from inlet to exhaust)?

Scenario 3: The first arriving company arrives to find smoke showing with moderate velocity and a bi-directional air track (smoke out the top and air in the bottom) from an open door on Side Alpha. A moderate volume of smoke is also pushing from around windows and from the eaves on Side Alpha. Flames are visible from several windows on Side Alpha (Alpha Bravo Corner) with a bi-directional air track (flames from the upper ¾ of the window with air entering the lower ¼). Performing a 360^o reconnaissance, the officer observes similar smoke and air track indicators on other sides of the building and that all doors and windows with the exception of the two windows and door on Side Alpha are closed. Returning to Side Alpha, the officer observes that the velocity of smoke from the open door has increased and flames at the interface between the smoke and air as it exits the doorway. Flames from the windows on Side Alpha are similar to when first observed. The home appears to have smoke throughout (smoke logged).

1. How do you think the fire will develop between arrival and initiation of offensive fire attack (assuming that adequate resources are on-scene for offensive operations) assuming no change in ventilation prior to fire attack.
2. How would the officer closing the front door prior to having a charged line at the doorway on Side Alpha (e.g., when performing the 360) impact fire development?
3. Assuming that sufficient resources are on-scene to permit an offensive attack and the door was closed during the 360, when should the entry point be opened? How should this task be approached?
4. How would horizontal ventilation of the fire compartment (Alpha/Bravo Corner) impact fire development if performed as soon as the hoseline is deployed to the open doorway on Side Alpha?
5. Once the hoseline is deployed into the building through the door on Side Alpha for offensive fire attack, should the door remain fully open or closed to the greatest extent possible? Why?
6. Assuming that this is a contents fire and horizontal ventilation will be appropriate, when and where should it be performed (describe the flow path from inlet to exhaust)?
7. Assuming that this is a contents fire and horizontal ventilation will be appropriate, when and where should it be performed?

These questions were all based on a similar fire (different development based on the ventilation profile at the time of the first company’s arrival) in the same, simple building, a one story, wood frame dwelling. It is important to examine other levels of involvement and ventilation profiles in this building as well as other types of buildings and fire conditions with similar questions. Also give some thought to the impact of door control when using vertical ventilation in coordination with fire attack.

Door Control Doctrine

Doctrine is a guide to action rather than a set of rigid rules. Clear and effective doctrine provides a common frame of reference, helps standardize operations, and improves readiness by establishing a common approach to tactics and tasks. Doctrine should link theory, history, experimentation, and practice to foster initiative and creative thinking.

Given what we know about the modern fire environment and the influence of both existing and increased ventilation on ventilation controlled fires, what guidance should we provide to firefighters regarding door control? The following questions are posed in the context of a residential occupancy (one or two-family home, garden apartment unit, townhouse, etc.).

1. If the door to the fire occupancy is open when the first company arrives, should it be (immediately) closed by the member performing the 360^o reconnaissance? If so why? If not, why not?
2. If the door should be closed immediately there any circumstances under which it should not? If there are circumstances under which the door should not be closed, what are they and why?
3. If the door is closed on arrival (or you closed the door during the 360o reconnaissance) when and how should it be opened for entry? Think about tactical size-up at the door, forcible entry requirements, and the actual process of opening the door and making entry? How might this differ based on conditions?
4. After making entry should the door be closed to the greatest extent possible (i.e., leaving room for the hoseline to pass)? If so why? If not, why not?
5. If the door should be closed to the greatest extent possible, who will maintain door control and aid in advancement of the line? How might this be accomplished with limited staffing?
6. If you are performing search, should doors to the rooms being searched be closed while searching? If so why? If not, why not? Are there conditions which would influence this decision? If so, what are they?
7. Should the doors to rooms which have been searched be closed after completing the primary search? If so why? If not, why not? Are there conditions which would influence this decision? If so, what are they?
8. How else can doors be used to aid in fire control or the protection of occupants and firefighters? Give this some thought!

Review The Influence of Ventilation in Residential Structures Part 2 for additional information on the influence of ventilation and door control as an  anti-ventilation tactic.

I plan on posting my thoughts on the questions posed in this post next week. However, it would likely make this much more interesting if you post your perspectives (or additional questions) as a comment!

Ed Hartin, MS, EFO, MIFireE, CFO

The importance of the initial Incident Commander conducting 360^o reconnaissance (or quickly obtaining information about conditions on sides of the building that are not visible) has been repeatedly emphasized in National Institute for Occupational Safety and Health (NIOSH) Death in the Line of Duty reports. This is important to assess both building and fire conditions. However, the building was there prior to the alarm of fire. Situational awareness (SA) does not only apply on the fireground, it must begin well before response. In structural firefighting, the built environment (including the building, its contents, and surroundings) are the ground we fight on and in. Situational assessment and size-up must be ongoing.

View from the Street

The Knead & Feed (see photo below), is an excellent restaurant in Coupeville, WA that serves breakfast and lunch. At first glance this building appears to be an older, one-story, wood frame, commercial with the Delta Exposure being a two-story building of similar construction. Given the age of the buildings, it would be reasonable to assume that they are of balloon frame construction. Looking beyond the building you can see Penn Cove, which provides an excellent view from the back of the restaurant.

Reconnaissance on Side C

However, the view in this photo begs the question, what’s on Side C? Access to Side C is via an exterior stairway on Side Bravo. Descending this stairway provides access to another kitchen and dining area in the Basement which is not accessible from the interior of the restaurant on Floor 1. Continuing down the stairway, provides access to a bakery at the Basement 2 level. The stairway then continues down to the beach, providing access to Side C…provided that it is low tide.

Obviously you get a considerably different picture from Side C! However, this is only the beginning of the story.

The Rest of the Story

It may appear that the small, one-story section of building between the Kneed and Feed restaurant and Exposure Delta is part of the exposure due to the color of the building on Side Alpha and the roof line on Side Charlie. However, this assumption would be incorrect as this is the main kitchen for the Kneed and Feed Restaurant.

There is no interior access between Floor 1 and the Basement (in either the Kneed and Feed or Exposure Delta). The Basement and Basement 2 levels of the Kneed and Feed are accessed from the exterior on Side Bravo. The Basement of Exposure Delta (apartment unit) is accessed from the exterior on Side Delta. The second floor of Exposure Delta is accessed from the interior.

Continuing down to the Basement level, the section of the building below the main kitchen contains an unprotected stairwell that is open to the underside of the Basement of Exposure Delta and the void space under the wood sidewalk that runs in front of the restaurant and Exposure Delta. The Basement and Basement 2 levels are interconnected this stairway (non-fire rated doors provide access between the stairway and the Basement and Basement 2. This stairway is framed in at the Basement level, but simply enclosed by wood slats at the Basement 2 level.

Strategic and Tactical Implications

This building presents considerable challenges due to its construction, configuration, attached exposure on Side Delta, and limited access. The following questions provide a starting point for discussion of strategic and tactical implications for this building and its most significant exposure:

1. How might the construction and configuration of this building and exposure impact on the B-SAHF (building, smoke, air track, heat, and flame) indicators presented during a fire? How might this vary based on location (Floor 1, Basement, Basement 2)?
2. How might the open stairwell between the Kneed and Feed and Exposure Delta impact on fire development and spread if the fire originated at one of the basement levels, or within the stairwell itself? How might communication between the stairwell and the wooden sidewalk on Side A impact firefighting operations (note that the sidewalk and void space below extends beyond the access points for Sides Bravo and Delta).
3. How would the open framing under the Basement of Exposure Delta impact on potential for fire spread from the Kneed and Feed to Exposure Delta (particularly if a fire originated on the Basement or Basement 2 level)
4. How would tidal conditions impact on access to Side Charlie for firefighting operations or placement of ladders for rescue or secondary egress from the Kneed and Feed or Exposure Delta (particularly the apartment unit in the Basement of Exposure Delta).
5. What strategies and tactics would provide the safest and most effective approach to confining and extinguishing a fire in each level of this building?
6. Given the significant threat to Exposure Delta should a fire occur in the Kneed and Feed, what strategies and tactics would be most effective in evacuating the occupants of this building and preventing extension?
7. Given the multiple occupancies (restaurant, retail, and residential), how would time of day impact on firefighting operations in this building and exposure?

While this building is in my response area, you have challenging buildings in yours as well. Time to find out what’s in your patch! When on a medical response, automatic alarm, performing fire inspections, or just eating breakfast, take the time to look around and ask yourself what if…. Building Factors are the first element in B-SAHF and they are present prior to the fire. Pre-incident planning either on a formal basis (best choice) or informally as an individual or company is essential to safe and effective incident operations.

Thanks!

I would like to extend a special thank you to the owners and staff of the Kneed and Feed for providing the opportunity to learn about their building. While challenging from a firefighting perspective, this is one of the best places to have breakfast or lunch (but particularly breakfast) in our District! If you are on Whidbey Island, stop in for a meal, but bring your appetite.

There has been an increasing awareness that smoke is fuel and that hot smoke overhead results in thermal insult (due to radiant heat transfer) and potential for ignition. However, the hazard presented by smoke as gas phase fuel can extend a considerable distance from the current area of fire involvement.

Reading the Fire

Print a copy of the B-SAHF Worksheet. Use the worksheet to document observed fire behavior indicators as you watch the first six minutes of the following video of an apartment fire that occurred on May 10, 2013 at the corner of Park Creek Lane and Hill Park Court in Churchville, NY. In particular, focus on fire behavior indicators that may point to changes in conditions. Don’t focus too much on the flame indicators presenting from the area involved, but pay particular attention to Building, Smoke, and Air Track indicators.

The following satellite photo and view of the Alpha/Delta Corner prior to the fire are provided to help orient you to the incident location. You can also go to Google Maps Street View and do a walk around on Sides Alpha (Hill Park Court) and Delta (Park Creek Lane) to view all four sides of the building.

The following time sequence from the video of this incident illustrates the conditions immediately prior to and during the explosion. The extremely rapid increase in heat release rate during the explosion was not sustained (a transient event) as evidenced by conditions illustrated at 06:25.

Building Factors

This building is of Type V construction with a wood truss roof system. In a large apartment building such as this, the trussloft is typically subdivided with draft stops comprised of gypsum board applied to one (or both) sides of a truss to stop rapid spread of fire within the trussloft. Draft stops should be thought of as speed bumps rather than a barrier (such as a firewall that extends through the roofline). While draft stops slow fire and smoke spread, they do not stop it completely and it is common for smoke to spread beyond the fire area despite the presence of draft stops.

The small dimension framing materials used in truss construction have a high surface to mass ratio, increasing the speed with which they can be heated and increasing pyrolysis products in the smoke when heated under ventilation limited conditions.

Note: The possible location of the draft stops is speculative as specific information regarding the construction of this building was not available at the time of this post. However, draft stops may be provided between the trussloft between units or based on the size of the trussloft without regard to the location of walls between units. Preplan inspections provide an opportunity to examine building factors that may be critical during an incident!

Smoke and Air Track Indicators

An important air track indicator in this incident was the strong wind blowing from the Alpha/Bravo Corner towards the Charlie/Delta Corner. The wind may have had some influence on ventilation in the trussloft above Exposures Bravo and Bravo 2, and definitively influenced other Smoke and Air Track indicators.

From the start of the video light colored smoke is visible at the peak of the roof above Exposure Bravo and Bravo 2, indicating that smoke had infiltrated areas of the trussloft that had not yet become involved in fire. Smoke that is light in color may be comprised of pyrolysis products and air and may be to lean or too rich to burn or it may be explosive See the video Smoke on the Firegear website for a good discussion of the characteristics of smoke (note that this video is currently undergoing validation).

The volume and color (smoke indicators), velocity and direction (air track indicators) above exposure Bravo 2 vary considerably from the start of the video until shortly before the explosion that occurred at 06:12 in the video. At 02:52 a firefighter entered Exposure Bravo 2 and a short time later at 03:47 a hoseline (dry) was stretched into this exposure and charged. It is unknown from watching the video if the firefighters on this line advanced to Floor 2 or if they took any action to change the ventilation profile (other than opening the door on Floor 1, Side Alpha). The exited after the explosion, but without haste, so it is likely that they were not on Floor 2 at the time of the explosion.

Smoke Explosion

Smoke explosion is described in a number of fire dynamics texts including Enclosure Fire Dynamics (Karlsson and Quintiere) and An Introduction to Fire Dynamics (Drysdale). However, Enclosure Fires by Swedish Fire Protection Engineer Lars-Göran Bengtsson (2001) provides the most detailed explanation of this phenomenon. Paraphrasing this explanation:

A smoke or fire gas explosion occurs when unburned pyrolysis products and flammable products of combustion accumulate and mix with air, forming a flammable mixture and introduction of a source of ignition results in a violent explosion of the pre-mixed fuel gases and air. This phenomenon generally occurs remote from the fire (as in an attached exposure) or after fire control.

In some cases, the fire serves as a source of ignition as it extends into the void or compartment containing the flammable mixture of smoke (fuel) and air.

Conditions Required for a Smoke Explosion

The risk of a smoke explosion is greatest in compartments or void spaces adjacent to, but not yet involved in fire. Infiltration of smoke through void spaces or other conduits can result in a well-mixed volume of smoke (fuel) and air. Smoke explosion creates a significant overpressure as the fuel and air are premixed and ignition results in a very large energy release. Several factors influence the violence of this type of explosion:

• The degree of confinement (more confinement results in increased overpressure)
• Mass of premixed fuel and air within the flammable range (more premixed fuel results in a larger energy release)
• How close the mixture is to a stoichiometric concentration (the closer to an ideal mixture the faster the deflagration)

Potential Smoke Explosion Indicators

It is very difficult to predict a smoke explosion. However, the following indicators point to the potential for this phenomenon to occur:

• Ventilation controlled fire (inefficient combustion producing substantial amounts of unburned pyrolysis products and flammable products of incomplete combustion)
• Relatively cool (generally less than 600^o C or 1112^o F) smoke
• Presence of void spaces, particularly if they are interconnected
• Combustible structural elements
• Infiltration of significant amounts of smoke into uninvolved compartments in the fire building or into exposures

Preventing a Smoke Explosion

As it is difficult to predict a smoke explosion, there are challenges to preventing their occurrence as well. However, general strategies would include 1) preventing smoke from accumulating in uninvolved spaces or 2) removing smoke that has accumulated remote from the fire (e.g., in attached exposures), or 3) a combination of the first two approaches.

Tactics to implement these strategies may include:

• Pressurizing uninvolved spaces with a blower to prevent infiltration of smoke. This involves use of a blower for anti-ventilation by applying pressure without creating an exhaust, similar to what is done to pressurize a highrise stairwell. It is essential to check for extension prior to implementing this tactic!.
• Horizontal ventilation of attached exposures to remove smoke, checking for extension, and then pressurization with a blower to prevent continued infiltration of smoke. If fire extension is found, pressurization without an exhaust opening must not be implemented!

Additional Resources

The following previous posts on the CFBT-US Blog may also be of interest in exploring the smoke explosion phenomena.

• Smoke Explosion or Backdraft
• Fire Gas Ignitions
• Language and Understanding: Extreme Fire Behavior
• Extreme Fire Behavior: An Organizational Scheme (Ontology)
• Gas Explosions
• Sudden Blast
• Explosions During Structural Firefighting

References

Bengtsson, L. (2001). Enclosure Fires. Retrieved May 12, 2013 from https://www.msb.se/RibData/Filer/pdf/20782.pdf .

This post will finish up with Captain Mike Sullivan’s Fire Attack Questions. In the coming weeks I will explore the research conducted by UL, NIST, and FDNY on Governors Island last summer (see the video of a presentation on this research at FDIC later in this post). If you have questions or topics that you would like to see addressed in the CFBT-US Blog, please comment on the post or send me an e-mail.

In your Blog about gas cooling you mention combustion products and pyrolysis products. Combustion products being light heat and smoke but can you elaborate on pyrolysis products, are they just the gasses that are off gassing from the fuel?

Smoke is a complex aerosol comprised of gases, vapors, and particulates resulting from pyrolysis and incomplete combustion along with entrained air. So, smoke is comprised of both chemical products of pyrolysis (thermal decomposition of fuel) and combustion products. The chemical composition of smoke is extremely complex and depends on both the type(s) of fuel and conditions under which it is burning, predominantly limitations on ventilation and oxygen concentration.

Smoke is toxic, with incomplete combustion of organic fuels producing substantial amounts of carbon monoxide and nitrogen containing materials producing hydrogen cyanide. As smoke is a product of pyrolysis and incomplete combustion, it also contains a substantial percentage of unburned fuel, as such, smoke is fuel.

I have read that if smoke is venting from a building then there will be air entering from somewhere. During basement fires where the fire is below the neutral pressure plane you will often see smoke exiting from the front door from top to bottom of the doorway with no apparent entry of air (no neutral pressure plane) and no other vent opening. Could you comment on this?

The mass of smoke exiting from the building must equal the mass of the oxidized fuel and the mass of air entering the building as mass can neither be created or destroyed (law of conservation of mass) as illustrated below.

If you see smoke exiting from an opening with a unidirectional air track (out), air is entering somewhere else. Likely, air is entering from multiple locations without presenting an obvious indicator as to the flow paths involved.

Controlling the flow path in this case, involves closing the door. This acts in the same manner as closing the damper in a wood stove. Restricting the exhaust will slow intake of air and reduce the heat release rate until water can be applied (preferably making access through an exterior doorway at the basement level or applying water through a window to further reduce heat release prior to an interior attack.

Recent research by Underwriters Laboratories (UL), National Institute of Standards and Technology (NIST), and the Fire Department of the City of New York on Governors Island showed that closing an open front door reduced the heat release rate from a basement fire. Battalion Chief George Healey, Dan Madryzkowski, Steve Kerber, and Lieutenant John Ceriello provided an excellent presentation on this research at the 2013 Fire Department Instructors Conference. I strongly recommend viewing the presentation (embedded below)!

Scientific Research for the Development of More Effective Tactics

The following video recording provides an excellent overview of research conducted by UL, NIST, and FDNY on Governors Island to develop an understanding of fire dynamics in the modern fire environment and the influence of firefighting tactics on firefighter safety and effective fire control and ventilation operations.

This presentation was a seminal event in the US Fire Service that emphasized the importance of understanding fire behavior and the connection between solid research (both in the lab and in the field) with operational strategies and tactics. The research is solid, but it is important that all of us understand that it does not answer all of the questions and we should consider context when attempting to apply specific findings in general terms. For example:

• The suppression elements of the Governors Island tests were conducted using solid stream nozzles as that is the predominant type of nozzle used by FDNY. Tests showed that positive impact can be had using this type of nozzle. An important finding, but it was not intended to address the question of where are solid streams more effective than fog patterns (and where fog patterns are more effective).
• Tests were conducted on the Vent, Enter, Isolate, and Search (VEIS) tactic. Evidence points to the importance of controlling the flow path by closing the door. This does not mean that this is or is not an appropriate tactic under all circumstances or in all contexts, it simply addresses the importance of controlling the flow path.

The fire service owes a tremendous debt to UL, NIST, and FDNY (and in particular George, Dan, Steve, and John) for their commitment to improving firefighter safety and the effectiveness of firefighting operations. In order to maximize the value of this critically important research, it is essential that we explore the findings and underlying data and make sense of how this information can improve firefighting operations in our communities. More on this in subsequent posts!

Ed Hartin