Exposure meters are not calibrated for infrared radiation, and the ratio of infrared to visible radiation varies with the light source.
Make trial or bracketing exposures over a five-stop range to determine the proper exposure for your application.
Under average conditions, use the following speed ratings to make starting-point exposures with handheld meters or through-the-lens light meters.
For through-the-lens camera meters, make your readings before mounting the filter over the lens. Then ignore the meter reading/readout after attaching the filter.