Your company entered into a lease with the business center with a specific rent price based on the amenities the building had at the time you entered into your lease. It is unlikely that you have the right to require the landlord to install a new security system at his expense without increased rent. The most important thing you can do is to review your lease. In a commercial lease, the parties have great flexibility in allocating responsibilities related to the property.
If the lease does not provide you a right to require the landlord to provide security upgrades and the new system is important to the tenants, they should research what the new system would cost to install and operate. Perhaps if they can agree on a way to split these costs between them, the landlord would be willing to allow the change.
You can reach Harkess & Salter LLC at (303) 531-5380 or info@Harkess-Salter.com. Stephen Harkess is an attorney licensed in the state and federal courts of Colorado. This answer is for general information only and does not create an attorney client relationship between Stephen Harkess or Harkess & Salter LLC and any person. You should schedule a consultation with an attorney to discuss the specifics of your legal issues.
Commercial leases come with an implied warranty that the property is fit for its intended use. Courts have held that things like leaking roofs and inadequate drainage violate this implied warranty. It is unlikely that a court would agree that the landlord's failure to install a buzz-in system violates this warranty unless you can demonstrate that the inadequate security impacts the intended use of the property.