Richard:
Try the guidance documents at:
http://www.fda.gov/cdrh/guidance.html
or you might find this site helpful
http://www.fda.gov/cdrh/comp/gmp.html
Using calibration as an example, what you need is in the regulation and it's probably what you have covered in your current procedures.
Sec. 820.72 Inspection, measuring, and test equipment.
(a) Control of inspection, measuring, and test equipment. Each
manufacturer shall ensure that all inspection, measuring, and test
equipment, including mechanical, automated, or electronic inspection and
test equipment, is suitable for its intended purposes and is capable of
producing valid results. Each manufacturer shall establish and maintain
procedures to ensure that equipment is routinely calibrated, inspected,
checked, and maintained. The procedures shall include provisions for
handling, preservation, and storage of equipment, so that its accuracy
and fitness for use are maintained. These activities shall be
documented.
(b) Calibration. Calibration procedures shall include specific
directions and limits for accuracy and precision. When accuracy and
precision limits are not met, there shall be provisions for remedial
action to reestablish the limits and to evaluate whether there was any
adverse effect on the device's quality. These activities shall be
documented.
(1) Calibration standards. Calibration standards used for
inspection, measuring, and test equipment shall be traceable to national
or international standards. If national or international standards are
not practical or available, the manufacturer shall use an independent
reproducible standard. If no applicable standard exists, the
manufacturer shall establish and maintain an in-house standard.
(2) Calibration records. The equipment identification, calibration
dates, the individual performing each calibration, and the next
calibration date shall be documented. These records shall be displayed
on or near each piece of equipment or shall be readily available to the
personnel using such equipment and to the individuals responsible for
calibrating the equipment.