NFPA 921 – 23.1.4 Definition of an Explosion

NATIONAL STANDARD: NFPA 921 – 23.1.4 Definition of an Explosion “Although an explosion is almost always accompanied by the production of a loud noise, the noise itself is not an essential element in the definition of an explosion. The generation and violent escape of gases are the primary criteria for an explosion.”   NIST INVESTIGATION: FAQ 13 13. Did investigators consider the possibility that an explosion caused or contributed to the collapse of WTC 7? Yes, this possibility was investigated carefully. NIST concluded that blast events inside the building did not occur and found no evidence supporting the existence of a
Read More

NIST – No Blast Sounds Heard

NIST FAQ “13. Did investigators consider the possibility that an explosion caused or contributed to the collapse of WTC 7? Yes, this possibility was investigated carefully. NIST concluded that blast events inside the building did not occur and found no evidence supporting the existence of a blast event. In addition, no blast sounds were heard on the audio tracks of video recordings during the collapse of WTC 7 or reported by witnesses. According to calculations by the investigation team, the smallest blast capable of failing the building’s critical column would have resulted in a sound level of 130 decibels (dB) to
Read More

Col. George Nelson

Col. George Nelson, MBA, U.S. Air Force (ret) – Former U.S. Air Force aircraft accident investigator and airplane parts authority.  Graduate, U.S. Air Force War College.  34-year Air Force career. Licensed commercial pilot.  Licensed airframe and powerplant mechanic.   Impossible to Prove a Falsehood True: Aircraft Parts as a Positive Clue to Aircraft Identity by George Nelson Colonel, USAF (ret.) Originally posted on Physics911.net – link to physics911.ca The precautionary principle is based on the fact it is impossible to prove a false claim. Failure to prove a claim does not automatically make it false, but caution is called for,
Read More

$elling out the Investigation – Bill Manning

From Article written by Bill Manning and published on January 1st, 2002 for Fire Engineering. BY BILL MANNING Did they throw away the locked doors from the Triangle Shirtwaist Fire? Did they throw away the gas can used at the Happyland Social Club Fire? Did they cast aside the pressure-regulating valves at the Meridian Plaza Fire? Of course not. But essentially, that’s what they’re doing at the World Trade Center. For more than three months, structural steel from the World Trade Center has been and continues to be cut up and sold for scrap. Crucial evidence that could answer many
Read More

NFPA 921 – 19.4.8.2.6 Extremism

NATIONAL STANDARDS: NFPA 921 – 19.4.8.2.6 Extremism “Extremism-motivated firesetting is committed to further a social, political, or religious cause. Fires have been used as a weapon of social protest since revolutions first began. Extremist firesetters may work in groups or as individuals. Also, due to planning aspects and the selection of their targets, extremist firesetters generally have a great degree of organization, as reflected in their use of more elaborate ignition or incendiary devices. Subcategories of extremist firesetting are identified as follows. (a) Terrorism. The targets set by terrorists may appear to be at random; however, target locations are generally
Read More

NFPA 921 – 19.2.4 – Exotic Accelerants

NATIONAL STANDARDS: NFPA 921 – 19.2.4 – Exotic Accelerants.  Mixtures of fuels and Class 3 or Class 4 oxidizers may produce an exceedingly hot fire and may be used to start or accelerate a fire.  Thermite mixtures also produce exceedingly hot fires.  Such accelerants generally leave residues that may be visually or chemically identifiable.   Exotic accelerants have been hypothesized as having been used to start or accelerate some rapidly growing fires and were referred to in these particular instances as high temperature accelerants (HTA). Indicators of exotic accelerants include an exceedingly rapid rate of fire growth, brilliant flares (particularly
Read More

NFPA 921 – 18.15 Analyze Fuel Source

NATIONAL STANDARDS: NFPA 921 – 18.15 Analyze Fuel Source. “All available fuel sources should be considered and eliminated until one fuel can be identified as meeting all of the physical damage criteria. For example, if the epicenter of the explosion is identified as a 6ft (1.8 m) crater of pulverized concrete in the center of the floor, fugitive natural gas can be eliminated as the fuel, and only fuels that can create seated explosions should be considered.   Chemical analysis of debris, soot, soil, or air samples can be helpful in identifying the fuel. With explosives or liquid fuels, gas
Read More

NFPA 921 – 18.12.2 High Explosives

NATIONAL STANDARDS: NFPA 921 – 18.12.2 High Explosives “…The effects produced by diffuse phase (i.e., fuel-air) explosions and solid explosives are very different. In a diffuse phase explosion (usually deflagration), structural damage will tend to be uniform and omnidirectional, and there will be relatively widespread evidence of burning, scorching, and blistering. In contrast, the rate of combustion of a solid explosive is extremely fast in comparison to the speed of sound. Therefore, pressure does not equalize through the explosion volume and extremely high pressures are generated near the explosion. At the location of the explosion, there should be evidence of
Read More