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Little Bang Theory: Mechanical processes that enhance safe and effective NFDD use

Noise Flash Diversionary Devices (NFDD) or "flash bangs" are standard SWAT tools of the trade. When used as intended by properly trained personnel, they reduce the risk of death and serious injury for everyone involved. When used outside of that environment, the opposite is likely to occur.

Flash bangs are designed to be loud and bright, and from a physics perspective they can't be either without generating heat and overpressure. Common devices are in the 3,000 degree/10,000 PSI range at the epicenter of the blast, with energy levels dropping off dramatically as the shock wave moves outward over time and distance. Unfortunately, body parts directly exposed in close proximity to the device are subject to traumatic burn/blast injuries, and recognizing this is the key first step towards preventing such negative outcomes.

Primary Causative Factors:

Traumatic flash bang injuries are the direct result of intimate contact with the device, which generally occurs in one of three ways:

  1. Direct suspect contact at the moment of deflagration.
  2. Direct officer contact at the moment of deflagration.
  3. Direct officer/suspect contact (post blast) with a launched metallic NFDD body.

Intimate contact blast injuries - suspect and officer alike - are almost always caused by operator error. Suspects get injured when an improperly tossed device contacts their body at the moment of ignition. Officers get injured when they fail to properly control the NFDD spoon, and the device ignites while gripped in their hand. Both get injured when a metallic NFDD canister gets airborne after ignition, and terminates its flight upon contacting the human body.

The common denominator in each of these scenarios involves contact with the device either by toss, touch or flight. With that in mind, a number of progressive teams have adopted a prevention strategy that generally precludes even the possibility of such injuries, and enhances the flash bangs effects as well.

The Bang Stick:

The most effective way to prevent NFDD contact injuries is to prevent the device from coming in contact with people. Seems simple enough, but actually doing so requires a dramatic paradigm shift in the area of NFDD operational deployment.

The use of a mechanical device to control flash bang placement is nothing new. Progressive teams began building and using "bang sticks" in the late 1980's, thinking more about second story deployments than injury prevention. Commercial versions became available several years later, as more teams began using them to enhance the safety and effectiveness of their programs.

The basic concept involves physically attaching a non-bursting NFDD to a metal pole, and using this to directly control the placement of the device at the moment of deflagration. The "bang stick" dimensions vary, with most agencies using 1 ¼ inch pipe, cut and welded into a 6' by 3' foot 'L' shaped configuration. The 'bang stick' is prepared for use and operationalized in the following manner:

  1. The spoon is cut off approximately one inch below the fuze head. This allows the device to be secured to the pole, and ensures a snag free release in the cluttered operational environment.
  2. The device is attached near the end of the short leg using copious amounts of duct tape or metal hose clamps-fuze head facing the long leg. Please note that this technique only applies to non-bursting canister devices.
  3. The pull pin ring is then attached to sturdy wire rope, which is run through a series of eyelets down the long end of the "L". The eyelets must be secured at an angle that allows an unobstructed pull and certain release of the pin/spoon.
  4. The NFDD operator and bunker/cover team approach the insertion point. This is normally an entry room window away from the door to be breached. Positions of cover are taken on opposite sides of the glass, and the NFDD operator straightens the legs on the pin.
  5. At the appropriate time, the device is forced through the top of the window and pushed above the curtains towards the ceiling. The pin is pulled via the wire rope and ignition follows.

The primary benefit of this technique should be readily apparent: The bang stick precludes even the possibility of injuries occurring in the previously described manner-period. No tossing/contact errors. No "ignition in the hand." No flying body impacts. In a single step the agency reduces the probability of the most common NFDD injuries to zero, and adds two extremely important secondary benefits as well.

The technique draws the suspect's attention towards the NFDD deployment point, and away from the breaching elements entry point. This greatly enhances officer safety, as compared to the more common practice of breaching the door, visually inspecting the interior, tossing the device then stepping into the "fatal funnel."

Bang sticks enhance overall NFDD performance. Devices that go off on the floor generally lose a significant percentage of their effectiveness, as the light, sound and overpressure are shielded and absorbed by the furniture, carpet and other "tangle foot" that is routinely found between the suspect and the NFDD. The bang stick results in NFDD ignition 5 to 8 feet above the suspect, allowing the totally unshielded and often reflected effects to "rain" down upon him.

Considering the rationale outlined above, many contemporary teams now use bang sticks exclusively. Two notable exceptions include:

  • Scenarios that preclude access to entry room windows.
  • The unique case in which an NFDD is deployed spontaneously, and not as a part the original operations plan.


Noise flash diversionary devices are a valuable piece of police equipment. They can be lifesaving or life taking, depending on how they are used. The negative outcomes of the past should guide our training and operational decisions in the future, especially as it relates to deployment and use of the bang stick. Team leaders and operators must take direct action now to ensure that future deployments are exactly what they want them to be: safe, effective, and focused on reducing the potential for death or serious injury to persons on both sides of the badge.

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