After the high-profile mass shooting in Uvalde, Texas, where 19 students and two teachers were killed, many politicians who are opposed to stricter gun laws have been calling for "hardening" U.S. schools.

President Joe Biden signed rare, bipartisan legislation to address gun violence late last month. The law provides $1 billion in funding for schools to quote "create safe and healthy learning environments for all students" as well as an additional $300 million to go toward training and equipment that can help during a threat of violence.

The private security industry that focuses specifically on the education sector had projected revenue of $3.1 billion in 2021 and is expected to grow by more than 8% annually on average, according to research and consulting firm Omdia.

However, these estimates only look at the companies that provide technology that helps control who enters a school, such as cameras and electronic locks.

The Department of Justice, Department of Education and the Department of Homeland Security at the federal level each have programs that provide grant money to school districts for security upgrades. The Department of Justice has awarded more than $410 million in grants through the programs created under the STOP School Violence Act of 2018.

Security experts warn that the grant programs to help secure schools may not be sufficient.

"We've gone into schools where they've had a one-time shot-in-the-arm funding through a grant or a school board allocation for putting in additional cameras, for example, and we go in three or four years later, the cameras aren't working," said Ken Trump, president of National School Safety and Security Services. Trump is not related to former President Donald Trump.

"They have no budget at the school or school district level for maintenance, repair, replacement," Trump added. "Yet, there's this facade, this security theater that they made school safer when, in reality, a lot of the technology and equipment is not being used."

On top of inconsistent funding for schools to buy these services, the demand from parents and school districts also tends to ebb and flow based on news events.

This sporadic demand is affecting industry growth. When it comes to companies that provide security equipment and services to control who can access the building, the growth rates can vary from 5% to 15% depending on how many shootings took place in a given year, according to Omdia.

Watch the video above to learn about the growing school security industry, what fortification measures schools are taking and how much it costs.