Fireground Strategies: Metal Window Enclosures


To commence and sustain interior fire operations, a few things must be in place. First and foremost, we must be able to get in. Only slightly less important than getting in is providing support, usually in the form of ventilation, so that once in, we can stay in until the job is done. In addition, and even more important, is that if things go bad, we must also be able to provide additional ways out of the structure. Although this is not usually a problem in most occupied buildings, it is becoming increasingly more difficult in vacant buildings. Defeating security measures in vacant buildings used to be easier than in any other types of buildings, since the building was likely to be open to the elements or boarded up with flimsy plywood.

The trend of sealing up vacant buildings is on the rise and is not likely to subside. To that end, owners of these buildings are resorting to the use of more formidable security devices, both to keep out vagrants and to protect their liability in case a vagrant who has made the vacant building his home dies in a fire there. It is ironic that the very same people who would not provide shelter to a destitute relative are more than happy to sue someone on his behalf and collect monetary settlements if that relative should die in a fire that occurs in a vacant building that should have been sealed closed.

To this end, building owners and even some cities that own derelict properties have begun renting security mechanisms. These security rentals are in the form of metal screen-like enclosures that cover the windows and a heavy metal vault-like door and frame mechanism to cover the doors. Although the enclosures are often found only on the first floor, this is not always the case; they may cover all windows and doors. The window enclosures are constructed of heavy, galvanized sheet metal, approximately 15 gauge. A securing device connects this sheet metal to heavy metal bracing (which is nothing more than pieces of street sign metal, also called Versa-Bar® or Unistrut®). A securing device behind the window frame tightens the assembly; this creates an extremely strong barrier. The heavy metal doors are set in an equally heavy metal frame, which is secured to the building’s door frame in much the same way as the window enclosures, with additional locking built-in measures. Both these window and door enclosures are nearly impossible to force using conventional means (photo 1).

(1) Metal enclosures seal doors and windows and may be found on all floors. They may be various sizes. This photo was taken two days before the fire shown in photo 2 below gutted this building. Note the “Hazardous Vacant Building” markings. (Photos by author unless otherwise noted.)

Brute-force tactics will not work here. In North Hudson, New Jersey, a recent two-alarm fire that started in debris on the exterior spread into two closely spaced adjacent wood-frame buildings that employed these types of security measures. As the companies had never encountered these barriers before, they had an extremely difficult time getting into the doors and forcing the window enclosures (photo 2).

(2) Looking from the rear at the B side of the building, we can see the metal enclosures in place on the first-floor and basement windows. (Photo by Ron Jeffers.)

The key to defeating the devices is to first identify how they are secured. If you do not determine this, you will likely embark on a long, frustrating, and possibly dangerous campaign trying to defeat the devices.


Let’s discuss the windows first. We have identified three ways in which they are secured. Two necessitate a specific type of entry method; the third needs something totally different. There may be more types out there that we have not yet encountered—for example, I originally thought there was only one type. At the aforementioned fire, two other types were encountered, which necessitated different tactics to defeat.

The three types of securing methods we have come across are the following:

  1. metal tab and turnbuckle,
  2. anchor head and ratcheted cable, and
  3. side pin.

The first two methods of securing the metal enclosure are similar and may be interchanged. Consequently, we can use the same tool and a similar tactic to defeat them. The key to identifying their types is to look at the front of the enclosure and determine which type of device is protruding—metal tabs about the size of razor blades or nail-like anchor heads. Both will be flush with the metal of the enclosure (photo 3).

(3) The metal tab type securing device is on the left. The anchor-head type is on the right. They are easy to distinguish, which is key to defeating these enclosures.

In the metal tab and turnbuckle types, the metal tab pierces the metal window enclosure and is attached to a turnbuckle that is tightened between the framing behind the window and the enclosure. The metal tab, which appears on the exterior of the enclosure, will have an additional tab that protrudes at a 90° angle to the enclosure (photos 4-6).

(4) A close-up of the metal tab as it protrudes through the enclosure.


(5) The connection to the turnbuckle at the back of the enclosure. This is simple to defeat if you recognize it.


(6) The view of the metal bracing behind the window frame. Note the turnbuckles between the enclosure and the metal bracing.


In the anchor-head type, the anchor head is attached to the end of a metal cable that runs through the bracing material behind the window frame and into a device that employs a ratchet to pull the enclosure toward the frame, where the end of the cable is then bolted to secure it (photos 7-9).

(7) The anchor head protruding through the enclosure. It will be flush against the enclosure.


(8) A view from behind the enclosure. Note the cable attached to the ratchet mechanism set in the metal bracing.


(9) A close-up of the ratchet mechanism.


The rotary saw with the metal blade will be the tool of choice. Be advised that for all types of these windows, a reciprocating saw is not effective, because the metal is too heavy and will break the blades or it will require an unacceptable amount of time to complete the cutting.

To defeat the metal tab and turnbuckle, place the saw blade on an angle into the space just above where the tab sticks out at a 90° angle to the enclosure. Plunge the blade in for the full depth; it will sever the device. You can use the same procedure for the anchor head and ratcheted cable, except place the saw blade at the edge of and behind the head and plunge it in at an angle across the rear of the anchor head (photo 10).

(10) Place the saw blade right next to the metal tab and make a plunge cut. Note how the metal tab on the right has already been defeated.

You can also use the metal blade to make a triangular cut (three overlapping cuts)—much like a roof exam hole—around the anchor head or metal tab, with the anchor-head and metal-tab type connections, but it will take longer. You need to cut out only three securing devices and then swing the covering out of the way (photo 11). Although the three-cut and hinge method will get the enclosure out of the way, it is best to remove the entire enclosure for two reasons. First, this will turn the window into a door for additional egress from the interior. Second, leaving the enclosure in place will impede tip placement for ground ladder access to the window.

(11) The overlapping cut method will take longer but will get the job done. Make sure all cuts overlap, or the enclosure will not be released. This may still take some prying. It is best to remove the entire enclosure.

If you cannot see the securing devices by looking at the front of the enclosure, that is your cue that it is not the anchor-head or metal-tab type. The side pins will be on the top and bottom or on opposite sides of the edges of the enclosure. There will usually be four side pins on each enclosure, two on each side on the bottom and top, each about six to eight inches from either side. The side pins are attached to spring-loaded tabs on opposite ends of a metal bar that runs behind the metal enclosure. The metal bar is attached by cable to the metal framing behind the window frame. The side pins will be sticking through the small vents on the side of the enclosure where the tabs attach and the enclosure angles toward the building at a 45° angle (photos 12-14).

(12) The side pin protruding through the side vent holes at the bottom of the enclosure. There is another side pin directly across from this and on the top. The dotted lines show where to plunge the blade.


(13) A rear view. The spring-loaded bar can be seen attached to the enclosure. This one uses cables to secure the enclosure.


(14) The spring-loaded tab that you must slice through to defeat this window. This enclosure used a turnbuckle.


There are two ways to defeat this type of barrier. The first and quicker way is to use a metal saw. You must make the cuts in the correct places, or you will not defeat the securing devices. To defeat the device, make plunge cuts between the side pins and the building on the metal enclosure itself. Make sure the cut is the full depth of the saw blade and made adjacent to and between the side pins and the wall. In this way, you will sever the tab and release the support bracket behind the enclosure. You can make two cuts on the same side (top and bottom) and hinge the enclosure over or make cuts in both sides, cutting through all four pins, and remove the enclosure completely (photos 15-16).

(15) Plunge the blade into the space between the side pin and the wall. Note that the top side pin has already been cut here.


(16) Cut the top first and then move downward. Hinge the window out of the opening. This may require some additional prying.


The second way to defeat this type of securing device is to use a rabbit tool (HFT). The stronger the building exterior, the better this will work. Again, place the tool near the side pins, since these are the areas that need to be broken for entry. Pry the enclosure away from the wall, shearing the pins. Unfortunately, the rabbit tool method will not work on the other two methods of securing the enclosures. It is a waste of time to try, and you will probably damage the tool in the process.

Regardless of how the enclosure is secured or what method you use to defeat it, be careful to control the cut and the enclosure. You will most likely have to cut from a ladder, which is dangerous enough, but it becomes even more hazardous because the coverings are heavy and can cause injuries if not controlled when they come free. Removing these enclosures is personnel-intensive. A whole company or even several companies may be needed to remove these enclosures.

I do not recommend forcing entry from the interior, especially if there is a smoke condition. If you decide that this operation can be conducted, be careful where and what you cut. Do not cut the cable: It may be under tension and may snap back at the cutter. It is acceptable to cut the turnbuckle if it is present or cut the bar that spans the window opening. Again, if you are operating inside a building with no ventilation or no secondary means of egress available, you might not want to be in there.


There will be one of two types of enclosures. One has two keyholes in it, one on the top and one on the bottom. With the metal saw, make plunge cuts about one inch away from the keyholes and toward the edge of the door. This will sever the throws that hold the door in place (photos 17-19).

(17) Note the top and bottom keyholes and the frame in which the door is set. These are extremely heavy doors.


(18) The securing mechanism inside the doorway. [Photo by Firefighter Richie Velez, North Hudson (NJ) Regional Fire & Rescue.]


(19) The method of cut. Cut about one inch away from the keyhole. Note that the door may be further secured and may need additional entry techniques.


The second type of door enclosure will involve shearing a carriage bolt near the top of the door. Knock it through the door with the point end of a halligan. This will allow you to lift the operating handle and open the door. If this is not successful, attack the hinges with the saw. They will be exposed, allowing access with the saw blade, but will not allow the company to maintain the integrity of the door. If all else fails, cut a door in a door, which will chew up your blade but will get the job done. Usually, the door that is locked last will have the least number of securing devices on it, and the keyhole blade plunge or carriage bolt shear method will work on that door. This is usually the front door, but that may not always be the case. Be prepared for a challenge!


The metal, when cut, not only will produce sparks but also may be extremely hot from the fire in the building. In addition, the jagged edges produced by cutting will be sharp. Take all necessary precautions, and wear proper personal protective equipment including hand and eye protection.

If you force the door first and then the windows, you might jeopardize the safety of your personnel. Once the door is cut, quite possibly a dozen or so firefighters will enter with tools, hose, and other equipment. If the window enclosures are still in place, the ventilation opportunities will be zero. How long can these personnel operate without adequate ventilation in a decent fire condition?

Even more important is the requirement for secondary and additional means of egress. If you force the door first, there is likely to be a lag time between when firefighters enter and the window enclosures are removed. If things go bad, no additional ways out of an already questionable structure could mean disaster. If enough personnel are on hand to force the door and the windows, great, but hold back the attack until more window enclosures can be removed. If there are only enough personnel to remove only one enclosure, start with the windows. If the place lights up, the openings can be used for stream penetration.

Remember, this is a vacant building! Once inside, all of the dangers inherent in vacant structures are likely to be present. Risk a lot to save a lot. Risk nothing to save nothing. A burned-down vacant building is no longer a concern to us. What our personnel are risking their necks for today will be trucked away tomorrow.


You can help to ensure safety during forcible entry by employing the “CRAVE” acronym. Following are the components of the CRAVE approach.


  • Consider how many companies will be “eaten up” forcing entry. Call for help early.
  • Decentralize Command by placing command officers in areas of priority.
  • Be especially cognizant of potential hazards posed by the structure. It is vacant!
  • Be prepared for heavy fire or potential backdraft conditions caused by entry delays.
  • Keep your exposures covered.
  • Light up the area.
  • Safety is the overriding concern.


  • If enclosures cover only the first floor, scan the building for victims showing at upper floors.
  • If entry is to be made, use a thermal imaging camera and a lifeline and ensure ground ladders are raised to all sides of the building as additional egress paths.
  • If there is heavy fire, consider how far personnel will be committed for a search. If it has been burning a long time because of notification and/or entry delays, can anyone be left alive inside?
  • Always conduct a secondary search.


  • Ensure two water supplies.
  • Ensure lines are in place, charged, and ready to go before making entry.
  • Consider the potential direction of spread, and position lines to head it off.
  • Consider the feasibility of an attack without adequate ventilation. Hold the horses at the barn door until you can get the building opened up.
  • Don’t be afraid to darken the fire down from the outside first.


  • Closed-up buildings must be completely ventilated. Consider if you want your personnel operating inside a building that is not cooperating with ventilation efforts.
  • Be aware of the potential for heavy fire conditions even before enclosures are totally removed. Expect it as they are removed.
  • Metal chews up saw blades. Request additional crews, additional saws, blades, and fuel.
  • If possible, remove all window materials once the enclosure is removed. Sometimes only half the window was used for the framing materials. It will be necessary to remove the remaining glass and sash.

Extension Prevention

  • Consider exposures when opening up the building.
  • Stretch lines in anticipation of fire conditions erupting from removed enclosures.
  • Consider building construction and paths of least resistance when anticipating fire spread.

New technologies are cropping up with frightening speed and must be investigated if we are to stay safe. Don’t keep this information to yourself. For it to be of any real value, it must be shared with the entire fire service. There are many ways to do that, but first you have to get out in the street and look. You might be surprised at what you might come across.

Thanks to Newark Battalion Chief Jim “YJ” Weiss and North Hudson Regional Fire & Rescue Firefighter Lou Morales for their assistance with this article.

ANTHONY AVILLO, a 23-year veteran of the fire service, is a deputy chief in North Hudson Regional (NJ) Fire & Rescue, assigned as platoon commander of the 1st Division. He has a B.S. in fire science from New Jersey City University. He is an instructor at the Bergen County (NJ) and Monmouth County (NJ) Fire Academies. Avillo, an FDIC instructor, is also an editorial advisory board member of Fire Engineering. He is the author of Fireground Strategies (Fire Engineering, 2002), Fireground Strategies Workbook (Fire Engineering, 2003), and Fireground Strategies, Second Edition (Fire Engineering,2008).

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