Blasting can be scary to a homeowner or employees of a business. We understand your concerns and hope that the following information will help address those concerns, as well answer any questions you may have regarding blasting that is being performed near your property.
What types of licenses are required to conduct blasting?
Blasting is highly regulated by both federal and State explosives licenses and agencies. In addition, a commercial driver’s license with a hazardous materials endorsement is required.
Will the ground move during a blast?
Yes, there will be movement, but by using state of the art monitoring equipment and blasting techniques we can ensure safe and precise blasting to help minimize disruption to surrounding properties.
What is a Pre-Blast Survey?
The Pre-Blast Survey report documents existing defects in a structure such as cracks in a foundation or walls and is conducted by a third party construction professional. This survey contains pictures and notes of the current condition of the structure prior to the blasting operation.
Is the ground and air movement caused by the blast measured?
Yes. State-of–the-art seismographs are placed at the nearest structures to record the amount of vibration. Seismographs are sophisticated machines that measure both ground vibration and air movement (air blast). These seismographs can measure ground vibration in three directions, vertical, horizontal and by longitude. These seismograph readings help ensure blast-induced vibrations are within regulatory limits.
How much vibration will be felt in a house or business that is near the blast site?
Even normal activity like heavy footsteps or a slamming door, will generally produce high vibration readings on a seismograph. You will probably feel vibration from the blast and hear a blast noise. Keep in mind that although the human body is an excellent detector of vibration, it is a poor measuring device. The human body perceives vibration at velocity levels far below those needed to cause damage.
How do you blast close to a structure without causing damaging?
We use several methods such as designing shots that move parallel to structures and minimize pounds of explosives per delay to reduce vibration levels. These also include smaller hole diameters and pattern spacing. We also use a dirt blanket (cover) to confine the blast to eliminate fly-rock.
How are explosives stored?
On most projects explosives are not stored on the site. They are delivered by State and federally approved trucks with built-in explosive storage magazines.
Are there any warning before a blast?
Blasting regulations require usage of a set of warning signals before each blast. First, five (5) minutes prior to the blast you will hear a series of LONG audible signals for one minute. Then one (1) minute prior to the blast, a series of SHORT audible signals. Finally after the inspection of the blast you will hear one (1) PROLONGED audible signal, indicating that all is clear and safe.