## 1 Introduction
### Research and Objectives  
The detonation of explosives in the open air has been studied, analyzing amounts of explosive material and distances at which it detonates, with the aim of establishing safety zones, which implies previously determining the primary characteristic variables, as the air blast wave level.  
Experimentation in this field presents great technical and economic difficulties, which is why most evaluations are carried out by extrapolation from small-scale experiences or from computer model results.  
In the present study, two sets of full-scale tests were carried out. The first with small/medium explosive charges from 0.2 to 7 kg and the second trial with a large amount of explosive, from 25 to 84 kg (simulating terrorist bombs).  
Two factors were taken into account that will fundamentally influence it: the explosive charge and the distance to the focus of the explosion.  
To test the influence of these two factors, a campaign of air wave measurement tests was carried out with different charges and with sensors placed at different distances from the point of the explosion. With these tests, the intention was to obtain a model to predict the overpressure or magnitude of the air blast wave that is one of the factors influencing negatively on the environment and, in extreme cases, the main factor that affects the structures in outdoor detonations.  
The works were focused on the design of a full-scale test procedure that would allow the development of a predictive empirical method based on the model for calculating the equivalent mass of TNT.  
A total of 18 different Riodin explosive charges were formed, placing the sensor at six different distances from the focus of the explosion, with which a series of campaigns were carried out with a total of 90 air wave measurement tests produced by the detonation of gelatinous dynamite. With the results obtained, the pertinent adjustment of the TNT-equivalent mass calculation model was carried out, which was used to predict the effects generated by the air blast wave in the simulation processes of predefined scenarios.  
Subsequently, the outdoor detonation of 10 TNT charges was analyzed in order to adjust the model and determine its range. Therefore, the results obtained in this work from the measurement of the air wave pressure peak in 100 full-scale tests are presented and analyzed, in which industrial and military explosives were detonated in the open air, without confinement, in different amounts, the highest that the environment allows without affecting people, communication routes, or buildings, which will conclude with the proposal of a calculation methodology based on the experience.  
With all this, it was possible to develop a predictive model that allows assessing the overpressure generated by the detonation of a TNT-equivalent explosive charge. The results are useful to predict air blast waves in common open-air blasts, such as those carried out with shaped charges to demolish metallic structures. On the other hand, the results are also useful to determine the air blast wave overpressure in the case of large explosive charges detonated in the open air, such as accidental explosive detonation or terrorist bombs.  
It is important to point out the relevance of the results achieved after the detonation of large explosive charges (more than 80 kg) simulating a type of bomb frequently used by terrorists. Reproducing the explosion on a real scale, the results are fully representative of the overpressure produced by an explosion of these characteristics without the need to extrapolate the results of tests with small loads. In addition, the detonation was carried out with TNT, which can serve as a standard to compare with any other type of explosive.