Answers to your construction blasting questions

Answers to your construction blasting questions
Posted on 01/28/2022
small explosion from blasting line on a construction site

Have you been startled lately by occasional ground vibrations or rumbling near Lenexa City Center? It’s not an earthquake. The vibrations are caused by controlled blasting on construction sites, like the one on the northwest corner of 87th Street and Renner Boulevard.

Here are answers to some questions you might have about this construction method.

What is blasting used for?

Lenexa’s geography includes a lot of subsurface rock formations that make construction challenging. Blasting is the most cost-effective method for breaking rock. And it greatly reduces the time needed to complete construction work.

Developers use a small amount of explosive substance to break up the rock into smaller pieces. This allows them to more easily install infrastructure like stormwater, sewer and water lines, streets and foundations.

Does the City know about this?

Yes. Licensed contractors who plan to do blasting within Lenexa city limits must first acquire a blasting permit from the Lenexa Fire Department and complete a detailed blasting permit checklist.

What qualifications do blasters have to have?

Blasting companies and the individual blasters are licensed by the Kansas State Fire Marshal’s Office and Bureau of Alcohol, Tobacco Firearms and Explosives for the authorization to use explosives. They are required to obtain initial training to obtain a license and must complete continuing education in the use of explosives to maintain their license.

What safety precautions are taken?

The Fire Department’s checklist follows city code, state regulations, as well as requirements from the Bureau of Alcohol, Tobacco, Firearms and Explosives for storage and transportation of explosives.

Blasting is not allowed within 100 feet of any structure. Blasting companies must notify every residence within 1,000 feet of the blast line and offer pre-blast surveys for any structure within 500 feet of a blast line. The pre-blast survey documents all structural and cosmetic flaws present in those structures prior to blasting activities. They are completed by a third-party vendor.

Ground vibration standards are set to prevent damage to property or structures, and they are measured on-site using tamper-proof seismographs. The Fire Department monitors controlled blasting to make sure it doesn’t exceed City-permitted threshold requirements.

Is my home or business safe from blasting?

If blasting occurs near your home or business, you can expect to feel some vibration or shaking and hear some noise. Most of the energy from a blast is used to break rock, but some energy travels from the blast site in the form of ground and airwaves.

The limits set for blasting noise and vibration are conservative and are below the threshold of where damage is known to occur.

Why do some blasts feel stronger than others?

The type of blast, distance from the blast and amount of explosives used are factors that influence how a blast feels when the ground or airwaves reach your house. Your location on a property at the time of the blast also affects your perception of a blast.

If you are outside a house or building, you will tend to feel the ground vibrations through your feet and legs. If you are inside a house or building, you may sense the structure around you responding to the vibrations and could hear some objects rattle. This is why you and your neighbors may feel or describe blast vibrations differently.

What can I do to help protect my home and personal property?

The Fire Department encourages property owners to maintain a current video and/or photographic documentation of their property condition and personal belongings. This information can be crucial when attempting to obtain reimbursement for fires, floods, tornados and theft, as well as other less common occurrences like blasting operations near your property. These records should be maintained in a cloud-based server or off-site storage location so it is not damaged or lost in the same incident.

How long will blasting last on a site?

Blasting permits are valid for a specified 30-day period. Blasting work typically takes place over a period of several weeks. Extensions may be granted by the Fire Department based on the particular considerations of each individual project.

How frequently does the City issue blasting permits?

Each year the Lenexa Fire Department issues an average of six controlled blasting permits.

Have further questions? Contact the Lenexa Fire Department Prevention Division at 913.477.7990.

Published Jan. 28, 2022