/19 and larger:

Requests for IP address allocations of /19 or larger may require additional approval by ARIN before assignment. The request template must be submitted with the following additional information.

* Network engineering plans, including subnets, host counts, and hosts per subnet, with projected utilization rates and associated confidence levels of those projections for one and two years.
* Deployment schedule for the network, including major milestones for each subnet.
* Network topology diagrams.

Read more at CalREN Network.