Airblast Measuring

When a round is blasted in a tunnel, a concentrated airborne shock-wave known as an airblast propagates spherically in the direction of the tunnel portal. The shock wave can be very forceful, even for a small round. This can cause problems in built-up areas where there is little distance between the tunnel portal and neighboring properties, in some cases just a few tens of meters. Problems can also arise when blasting out deep foundations in the vicinity of people, buildings and other facilities.

Damage and anxiety
Compared with ground vibrations, airblasts can damage buildings in other ways and are unhealthy for people and animals. The propagation of an airblast depends on the weather and the wind. Even a small round in a quarry can create an airblast which people who live in the “wrong” direction can experience as forceful. To understand the reactions received from the ecological and structural surroundings of a quarry where blasting takes place, and also to be able to assess the risk of damage, it is therefore very important to measure not only the ground vibrations but also the airblast, i.e. the airborne shock-wave.

Measuring in accordance with standards
Nitro Consult has for many years measured airblasts as well, especially in connection with blasting. We therefore have great experience in the problematics of the measuring practice, gathered from a large number of assignments. We have also participated in the production of Swedish standards to regulate how airblasts should be measured and what limit values should apply.

Established standards serve as guidelines for both the measuring procedures and the interpretation of the results. Measurement procedures that comply with standards are most relevant for personnel who are responsible for assessing the effects of vibration etc and giving advice on the protective measures needed at worksites.

Producing standards that are easy to understand is an excellent way of making measurement results more usable. Moreover, since the recipients of measurement reports are often not familiar with vibration and measuring technology, referring them to a known standard can help them to both understand the measurement results and use them more effectively.