Security-conscious residents and businessmen often reinforce their doors by installing one or more tubular latches. The tubular bolt is the most common "add-on" lock because it is relatively cheap and easy to install. Although it operates through a simple mechanism, it can be a very powerful and challenging obstacle for a burglar or firefighter trying to enter forcibly. For a firefighter who underestimates its strength, a lock tongue that costs only $6 is a difficult test to force open the door.
In order to successfully and quickly force access to a door secured with a tubular bolt, the door must be of appropriate size and the correct tools and techniques must be used. The person performing the forced entry must be able to quickly identify the tubular bolts and thoroughly understand how they are installed and operated.
Generally, it is not difficult to identify the tubular bolt. Most can be easily identified by the typical large lock cylinder, which is usually installed 4 to 6 inches above the original door handle lock. The core assembly used for the tubular lock tongue is usually two to three inches in diameter and protrudes one-half to one-quarter of an inch from the door. This relatively large profile is necessary because the cylinder is mounted on the surface of the door. Only the back of the cylinder is slightly recessed in the hole on the door. The cylinder is fixed on the surface of the door by two screws, which are connected to another cylinder or thumb twist on the other side of the door. The two mounting screws screwed into the back of the cylinder mounted on the outside of the door actually squeeze the door between the two cylinders. Obviously, the diameter of the two cylinders must be larger than the hole in the door; otherwise, the mounting screws will pull the cylinders into the hole together. In order to increase their overall diameter, the lock cylinder for the tubular bolt is usually installed on the edge of a large lock ring. Some locks have a key bolt mechanism built into the large decorative eyelet. These accessories allow mounting screws to tighten the thumb on the inner and outer surfaces of the door and facilitate the pulling of the cylinder by providing a point of purchase for prying tools.
Rotating the lock cylinder or the internal thumb activates the lock tongue, which slides out of the tubular shell embedded in the edge of the door-hence the name "tubular". The bolt can extend up to two inches into the door frame. The lock cylinder is connected to the bolt mechanism through a tail piece, which transmits the turning action of the key to the lever at the end of the tubular housing, which causes the bolt to extend and retract. You can see the tip of this lever on most bolts. It is visible behind the bolt, recessed in a notch at the top of the tube. When the lever slides the latch in and out of its striking position on the door frame, the range of motion of the lever is approximately 10 to 2 o'clock or 2 to 10 o'clock.
Enforcement starts with zoom in
When firefighters assess barriers to entry and fire conditions, effective and professional forced entry operations begin on scale. The information obtained in the enlargement of the size has a profound effect on the selection of mandatory entry, the selection of tools, and the method of determining the acceptable degree of damage to the property. The following are some factors that firefighters should consider before starting to deal with a door locked with a bolt:
How is the door constructed and how strong is the door?
How are the door frames and adjacent walls constructed? How strong are they? Look out the door. The wall structure determines the degree to which the door frame can bend away from the door. Zooming in may indicate that breaking a wall is faster and easier than struggling with a difficult door.
Is the door facing or away from forcibly entering the team?
What are the strength, design and operating characteristics of the lock?
What is the brand name of the lock? The brand name can describe many aspects of the lock—for example, its strength, design, and resistance to forced entry. Paying attention to the brand names of locks that are particularly difficult to force can save firefighters a lot of time and effort. Forced to enter the team can immediately call power tools or choose other ways to enter.
Is the door locked with a single latch or a double latch? Single or double is related to the number of lock cylinders on the bolt lock, not the number of bolts. The single latch door has a lock cylinder on the outside and a thumb turning device on the inside, which can be operated without a key. The double latch has a cylinder on both sides of the door, of course, a key is needed to open the door from the inside. Whether there is a single deadlock in a building is important information and should be determined through pre-fire planning. For example, based on prior knowledge, a fire company can unlock the door by punching a small hole in the plasterboard wall, reaching in and turning the thumb to unlock the door, thereby quickly entering the apartment from the public corridor.
However, thumb rotation is becoming less common because many people feel safer to install a lock cylinder on the inside of the door. Unfortunately, double latches are extremely dangerous for occupants of structural fires and firefighters who must enter and search for occupants. People who lock doors with double door latches rarely follow the advice of our public education program, which urges them to keep the key in the lock, or at least keep it next to the door when they are at home. Some of these people will become dead, locked in their own homes. Flames, smoke or fire gases will prevent residents from getting their keys in time to escape. The firefighter encountered the lock cylinder on the inside of the door, and if he was cut off from the door he entered, he would have to force it out. Unless you know otherwise, always assume that a door is locked with a double latch. Carry a forced entry tool with you when searching, in case you have to get out of a door or window. Never expect to leave the building easily through a door that is different from the door you entered. The other door can be locked with a double latch.
What are the fire conditions? The degree of fire development in the building determines the hazard to life and the urgency of forced entry. The severity of smoke and fire can strongly influence the choice of method for forced door opening. Deteriorating fire conditions and lack of visibility will severely limit the skill or physical exertion required for certain forced entry methods.
Traditional forced entry uses the power of hand tools maximized through leverage and skill to overwhelm the door and lock assembly. Compared with more complicated forced entry methods, you can enter faster by prying or knocking on a door locked with a tubular bolt. Although almost any door will eventually succumb to an axe, a mallet or a Halligan door, traditional forced entry is most successful and suitable on wooden and light metal doors. Of course, heavy metal doors can be fixed with latches in the traditional way, but this requires more time, skill and physical exertion.
The goal is to apply force to the door frame and lock assembly until one of them fails. Prying usually tears the wooden door or damages the wooden door frame at the location where the lock assembly is installed. Few wooden doors that open inward can withstand the impact of a 10-pound mallet. Knocking on the lock cylinder can drive the bolt through the wooden doorpost or knock the entire lock assembly through the door. How the lock fails depends on which is weaker: the door or the door frame. Pry open or hit a metal door, crush it and bend it away from the door frame, enough for the latch to clear its impact. Lock tongues, especially low-priced ones, can bend and break due to the shear force generated by hitting the lock or picking the door.
The success of traditional forced entry depends on the weakness of the door, lock or door frame, and the skill, strength and endurance of the firefighter. Therefore, before attempting this method, it is important to evaluate the strength and structure of the door and lock assembly. The size of a solid metal door locked with a deadbolt will clearly indicate the different methods of forcible entry.
The design and operation of most tubular bolts makes them susceptible to forced entry methods. This method may be the best choice for firefighters who have to forcibly open heavy steel doors without power tools. The lock-through method usually includes two steps: (1) remove the lock core; (2) use a screwdriver or a special key tool to replace the rotation of the lock string to operate the lock mechanism. An important variant of this method is generally more effective, because it is not always possible, necessary or even advisable to separate the cylinder from the tubular bolt to operate the internal locking mechanism. The following is an explanation of these two lock-through technologies.
Remove the lock cylinder. The core assembly for tubular bolt locks is usually too large to fit into the blade of a traditional "K" tool (designed to pull the mortise core) or similar zipper device. However, the size and the components mounted on the door surface make it possible to pull the tubular latch cylinder.
Drive a narrow wedge-shaped tool, such as a nail puller, halligan's adz, or a "K" tool specifically designed to be used with a tubular latch behind a collar or shield. A strong, close-fitting cylinder may require the narrow size of a sledgehammer-driven ax blade to gain an initial point of purchase. Insert the Halligan adz at this point and use a prying method to expand the gap between the cylinder and the door. The pulling force exerted by Halligan may damage the two mounting screws holding the lock cylinder in place or pull them out of the threads on the back of the lock cylinder. When this technique is successful, the result is usually quick and impressive: the cylinder cleverly pops out of the door.
Keep the cylinder intact. Strong, high-quality bolts made in the United States usually use large, hard-faced screws to secure their cylinders to the door. These sturdy mounting screws are specifically designed to resist the efforts of anyone trying to forcibly remove the lock cylinder. Even a bolt that is not too strong can be very strong, making it very difficult to remove the lock cylinder. This is not necessarily doomed to fail through the locking method.
If the cylinder won't yield, maybe the door will. Remember, every action must have a reaction. The action of pulling the lock core on the outside of the door is directly transferred to the lock core or the thumb on the inside of the door through the sturdy mounting screw. This action actually pulls the inner cylinder into the door. The door will most likely react by squeezing or collapsing the inner cylinder. Since Halligan's point of purchase is at the top of the outer cylinder, the pulling action tends to tilt the bottom of the cylinder into the door. The reaction may cause the door at the bottom of the outer cylinder to be crushed. No matter how or where the door is squeezed, it effectively reduces the thickness of the lock core, thereby expanding the space between the outer lock core and the door surface.
Continue to pull and pry until the hole drilled in the door shows a crescent-shaped opening above the top of the lock cylinder. The goal here is not to remove the cylinder, but to create an opening large enough to insert a screwdriver or pick and get a good view of the bolt mechanism. Pulling the cylinder farther may cause the locking mechanism to be misaligned or damaged to an inoperable level. Your goal is to slide the bolt in and out of the lever it hits. Use a pick (ice cubes, nuts, dental tools) or a small screwdriver to lift the tip of the lever from the notch at the end of the tube, behind the bolt. Now, move the lever back, away from the edge of the door. This action will push the bolt to its unlocked position.
This variation of the through lock method should be implemented at the first sign that the lock cylinder will not separate from the bolt mechanism. It is most effective (and suitable) for strong locks installed on weaker doors. Of course, any forced entry method will not always succeed. In order for this technology to work, the bolt must be accessible and maneuverable. Heavy smoke can obscure the visibility of the locking mechanism. A high-quality bolt manufacturer uses steel guards to prevent manipulation of mechanical devices. After the lock-through method fails, there are only three options to enter the team: try the traditional method, find another entrance or use a power tool.
A steel door reinforced with internal ribs and covered with thick metal plates can be a strong barrier, especially when it is locked with one or more high-quality bolts. Sturdy steel doors are usually suspended in steel frames of the same or greater strength. When this kind of door opens inward, it is particularly difficult to open it by force by traditional means, because you must pass the prying tool through a complete bunny door frame and around the edge of the door.
The hydraulic forcible entry tool is very suitable for combining heavy metal doors that open inwards and strong steel (rabbit) door frames. The hydraulic forced entry tool designed for inward opening doors works best when the open jaws are in contact with the solid solid door and rabbit-shaped steel door frame. Insert the hydraulic tongs between the door near the lock and the door frame. The hydraulic hand pump separates the jaws, forcing the door inward and destroying the integrity of the bolt.
Some lock manufacturers advertise that their bolts cannot be cut with a saw. They made this request because their lock had a strong hardened steel tongue, or a hardened steel rod that passed through the center of the tongue. These features can deter thieves who use hacksaws, but not firefighters who operate rotary saws.
On the door that opens outward, insert the alumina blade into the space between the door and the door frame, and saw through the bolt. However, the space between the door and the door frame must be wide enough to allow the composite blade to rotate freely without any restraint, which is very important. To expand this space, a Halligan advertisement was driven between the door and the door frame. If more clearance is needed, push Halligan down (tilt adz) to separate the door from the door frame further.
The rotary saw can also effectively cut the bolt on the metal door that opens inward. However, this process requires a skilled operator to cut the door along the door frame, because the space between the door that opens inward and the door frame cannot be directly accessed from the outside. Cut the door at the lock, as close to the door frame as possible. If the door handle is blocking your chin, pull the door handle. Guide the blade carefully as it cuts the door at a slight angle towards the door frame, but avoid cutting the door frame deeply. With proper technique, the saw will cleanly cut the bolt that is flush with the edge of the door.
A heavy-duty air chisel designed specifically for vehicle release, which can greatly enhance the ability of forcibly entering through locks. The air chisel will quickly cut the lock cylinder from the cheap bolt. For stronger locks, use an air chisel to cut an opening in the metal plate skin of the door so that the bolt mechanism can be operated without pulling the lock cylinder.
Tubular bolts are the most common and challenging locks that firefighters encounter when entering forcibly. Firefighters can improve their ability to lock doors with door latches by familiarizing themselves with the doors and locking devices in their jurisdiction. They should consult a locksmith in the area. They are an extremely valuable source of technical information about locks and new products launched by the lock industry. Obviously, many of the techniques used by locksmiths are too complicated for the fire scene, but locksmiths who are willing to provide expertise can help firefighters maximize the effectiveness of their tools and techniques. n
(Top) Two different locks show the change in strength of the cylindrical mounting screws. The bottom lock is a high-quality bolt using 516-inch surface hardened screws. It is specifically designed to resist attempts to forcibly remove the lock cylinder. The top lock is a good but not very strong bolt that uses smaller mounting screws to pull and separate the lock cylinder. The (bottom) lock cylinder is mounted on a large decorative eyelet, connected to the bolt mechanism through a tail, and transfers the turning action of the key to a lever that slides the bolt in and out of its tubular housing. When entering the device without removing the lock core, a screwdriver can be inserted to move the lever that pushes the lock tongue into the unlocked position. (Picture of Justin Vasilkowski.)
(Left and right pages) Wooden doors usually tear when they are pryed open when they are close to the lock assembly, so that the lock tongue can clear its impact on the door frame. (Upper left) Hit the cylinder with a sledgehammer to push the entire bolt assembly through a wooden door. (Upper right and lower left and lower right) Use the Halligan tool to pry and bend the metal door that opens inward, and make the double-cylinder bolt clear its impact. (Photo by W. Latimore.)
Three through lock operations: (upper left corner, middle) the ax blade is driven by a 10-pound maul to cut the bolt cylinder or obtain a purchase point to pull it. After the cylinder is removed, the door can be easily opened by operating the bolt mechanism with a screwdriver. (Photo taken by H. Pardo.) (Top right, middle left, middle right, bottom left) The steps of the method of threading a lock on a door locked with a tubular bolt. mual drives the adz end of the Halligan tool behind the escutcheon ring to obtain a point of purchase. The fireman pried Halligan up and pulled the lock cylinder away from the door. When the installation screw fails, the lock cylinder will pop out of the door (note that the lock cylinder falls in mid-air and is close to the lower lock tongue). The screwdriver is applied to the mechanism. (Bottom middle and right side) The hammer axe method is also suitable for opening iron safety doors with bolts. (Photo by Tom Kenny.)
(Upper left and right) Firefighters use a rotary saw equipped with alumina blades to enter the fire scene through an iron security door and a metal door, both of which are locked with a bolt. The latch and the door handle latch are flush with the door. (Photo of Ray Bell.) (Bottom left, right) The bolt on the heavy metal door that opens out was cut with an electric saw. It is important that the space between the door and the door frame is wide enough to allow the blade to rotate freely without being restrained. The adz end of Halligan is driven by maul, which expands the space between the door and the door frame. (Photo by W. Latimore.)
(Upper left and lower left) The hydraulic forcible entry tool can easily overwhelm the lock tongue on the metal door that opens inward. (Photo: W. Latimore.) (Bottom right) Cutting the bolt on a metal door that opens inward requires a skilled operator to cut the door carefully, as close as possible to the door frame. (Photo by Justin Vasilkowski.)
BILL GUSTIN is the captain of the Metropolitan Dade County (FL) Fire Department and the chief instructor of the department’s officer training program. He has taught firefighting skills for cruise ship crews, coached in Caribbean countries, and is a member of the International Rescue Working Group of the Office of Foreign Disaster Assistance in the United States. He is a member of the editorial advisory board of Fire Engineering.