WirelessHART requires a Network Manager, a Gateway and a minimum of five (5) WirelessHART field devices.
You will also need a Handheld master to configure the join key and network ID in the WirelessHART field devices.
The field instruments would need a WirelessHART Adapter if they are not WirelessHART products themselves. WirelessHART uses IEEE802.15.4 2.4GHz radios, with a range of 200m between devices within the network. It is recommended to use two (2) Gateways for redundancy.
Attached is a WirelessHART Engineering Guide, see section 8.6 (Designing) for the rules of installation in order to have a healthy WirelessHART network.