Forcible Entry: Conducting The Size-Up

Providing entry at secured buildings is one of the most important operations that firefighters must perform. A high level of security is common in most urban areas, and is becoming more routinely encountered in the suburban areas as well.

Although primarily considered a truck operation, forcible entry is a skill in which all firefighters must be proficient. As difficult forcible entry situations arise, firefighters will be called upon to display a high level of skill and determination in order to gain entry in an efficient and timely manner.

Photo by Harvey Eisner
Although primarily considered a truck operation, forcible entry is a skill in which every firefighter must be proficient.


Photo by Robert Morris
A halligan tool is driven in to force a steel door.


The first step at any forcible entry operation is the size-up. There are five major points to consider in developing a good size-up:

  • Type of Response (Mission)
  • Method
  • Fire Conditions
  • Door Construction
  • Survey

Type Of Response

Photo by Robert Morris
The door is forced - the Segal lock is broken; the mortise lock is forced; and the door is bent.

The nature of the incident to which you are responding will determine how you carry out the forcible entry mission. The type of response can be broken down into tactical or routine operations.

  • Tactical. Working fires or other emergencies when prompt entry is needed to save life and/or property. Under these circumstances the forcible entry must be quick and reliable.
  • Routine. Non-fire emergencies such as an alarm investigation, odor of smoke or other non-life-threatening situations. At routine operations the primary concern is to limit the amount of damage done during entry.

Methods Of Forcible Entry

There are three basic methods of forcible entry: conventional, through-the-lock and power tools. Having a good working knowledge of each of them is the most important factor. These methods center on the tools and techniques used to force entry.

Conventional forcible entry is the oldest and most reliable method used. It involves the use of force, leverage and impact. The primary tools used in conventional forcible entry are the "irons," which consist of a halligan tool and a flat-headed axe. The axe is used primarily as a striking tool, so a heavier eight-pound axe with fiberglass handle is best. The 10-pound maul or a T-N-T may be used in place of the axe.

Several procedures can be employed to force a door conventionally:

  1. The door and the lock are forced away from the frame.
  2. The lock or striker is broken.
  3. The door frame is broken.
  4. The door is broken.
  5. Forcing the hinge side.
  6. Breaching the wall or door.
Photo by Robert Morris
A two-piece hydraulic forcible entry tool (HFT).


Photo by Robert Morris
Through-the-lock forcible entry - a "K" tool is used to remove a cylinder.


The type of door and the locking devices installed along with the prevailing conditions at the scene (heat-smoke-visibility) will dictate the proper technique to use.

In most cases conventional forcible entry using the irons is the quickest and most reliable method, therefore it is the primary means of entry at structural fires.

A variation of conventional forcible entry that is becoming widely used is the hydraulic forcible entry tool (HFT). The HFT has been found more effective than the irons in the following conditions, which are routinely encountered on the fire floor:

  1. Poor visibility - Striking with the axe and properly positioning the halligan into position is often difficult under poor visibility.
  2. Poor position - Narrow hallways and other obstacles that restrict working room make working with the irons difficult.
  3. Well-secured doors - Strong doors with several locks may be time and energy consuming.
  4. Inward-opening doors - The HFT is ideal for doors that swing away from you and have a steel frame.
  5. Lack of experience - Using the irons on a well-secured door requires great skill, which is gained only by doing the job several times. Using the HFT generally requires less skill.
Photo by Robert Morris
A firefighter uses a hydraulic forcible entry tool to force a hinge.


Photo by Robert Morris
Cutting an American 2,000 round padlock with a power saw equipped with an aluminum oxide disc.


The HFT is generally effective only on inward-opening doors that have a strong frame (metal) which is needed to anchor the jaw of the tool. On doors with a weaker wooden frame the jaws tend to rip through the wood and the tool does not get a good bite.

Where speed of entry is the primary concern, conventional is the way to go, but it must be remembered that there are many options to consider and practical experiences is the best teacher.

Photo by Robert Morris
An inside view of a steel door with rim locks. At the top is a vertical-bolt Segal lock. At the bottom is a double-bar Fox lock.

The through-the-lock method involves removing the lock cylinder with the proper tools and operating the internal locking mechanism. A good working knowledge of the types of locks you may encounter is extremely important when using this method, and will greatly improve your rate of success.

A wide array of tools can be used for through the lock operations. The "K" tool is widely used but has some limitations. Lock pullers such as the officers tool (O-tool), the "Rex" tool, the Sunila tool and others vary in their ability to pull the variety of lock cylinders. The halligan tool, "Bam Bam" tool and channel lock pliers can also be used to remove some types of cylinders. Once the lock cylinder has been removed, using the proper key tool can open the lock.

As with any technique, through-the-lock offers a variety of advantages, as well as some disadvantages. Generally it causes less damage, may result in quicker entry on some locks, and allows for the door to be re-locked following operations in many cases. Conversely, some cylinders may be difficult to pull, cylinder guard plates often slow down the operation, and several locks on a door may lead to confusion as to which locks are locking or unlocking.

When dealing with heavy security devices, such as roll-down steel gates with heavy-duty padlocks and other locking devices, power tools save valuable time and allow quick and reliable entry. The power saw, with an aluminum oxide disc, is the most versatile of the power tools. It is capable of opening most security devices in rapid fashion. The oxy-acteylene torch and, to a lesser degree, the MAPP torch, are also effective in many situations. The battery-powered sawzall also has the potential for some jobs.

Fire Conditions

The conditions under which we operate are important size-up considerations. The location and extent of fire as well as the potential for backdraft or flashover will have an effect on the method, timing and location of forcible entry. For example, the high heat and poor visibility commonly encountered on the floors above the fire may make the hydraulic forcible entry tool the best choice. If backdraft is suspected, you must wait for a charged hoseline and ventilation to take place before gaining entry.

It is important to maintain the integrity of the door during forcible entry to confine the fire and protect the means of egress. When heavy fire is suspected behind the door you are about to force, call for a charged hoseline of adequate size to be placed in position prior to entry.

Door Construction

Wood doors. Wood doors are constructed as solid, hollow or wood with a glass panel. They may be hung in wood or metal frames. Generally, wood doors are relatively easy to force as the door or frame will split and fail. Be aware that some wood doors will burn through quickly and allow the fire to extend. Doors with glass panels may allow quick entry by breaking glass, but beware that this will destroy the integrity of the door, letting smoke and fire out and complicating the forcible entry operation.

Photo by Robert Morris
A mortise lock with a spring latch and deadbolt.

If the door has double cylinder locks or locks that can't be opened quickly through the broken window, the door must now be forced conventionally with the added problems of heat, smoke, or fire venting from the opening made.

Glass doors. These are the most common entry doors to commercial and business occupancies. They may be metal framed with glass (most common) or all glass. Through-the-lock is usually the best method on these doors.

Steel doors. Steel doors are usually hollow or have wood-core interiors covered with metal. These doors vary in weight and strength. They are usually hung in steel frames. When they are set in masonry walls, they may be very strong, and can be challenging to force.

Locks and security devices. The types of locks, the number of locks, and their location is a major factor in forcible entry. Different locks will fail in a different manner. Knowledge of the characteristics of the locks you may encounter will increase your ability to gain entry. Some common locks widely used include the Mortise lock, knob and key lock, tubular deadbolts, rimlocks, slide bolts, and bars.


A visual and hands-on observation of the door is the final step of size-up and the first step of forcing the door. The survey consists of the following pages:

  1. Feel for heat.
  2. Try the door. Is it locked?
  3. Which way does the door swing?
  4. Check for resistance by pushing the door at the top, bottom and center.
  5. Force by best method.
  6. Maintain control of the door.

Knowledge, experience and the ability to keep cool under pressure are some of the traits the "irons man" must have. At many operations the forcible entry firefighter is the most important member and must perform well under all conditions.

Captain Robert Morris, a Firehouse® contributing editor, is a 25-year member of the FDNY and the commander of Ladder Company 28.