>>2937095The 22 degrees on the FP4 is just the film speed rating, equivalent to ISO 125.
Use Massive Dev Chart (use Mr. Google) to find the time for your specific developer and dilution of it. Check the chart, it will probably be listed for 20 degrees celsius. You can then find on the same website a tool to calculate the times at different temperatures.
Or you could cool your chemicals down to 20 degrees or whatever, but that might be more difficult for you, idk.