(1) Equipment sent to the Bureau must be properly packed to minimize likelihood of damage in shipment and handling. Suggestions on packing and shipping are made in some sections of the present schedule. In every case, the client should consider the nature of the equipment, pack it accordingly, and clearly label shipments containing fragile instruments or materials, glass, etc. The use of "security express" should be considered in shipping delicate instruments.

(2) Shipping charges both to and from the Bureau must be assumed by the client. It is generally impractical for the Bureau to pay shipping charges and add this cost to the billing invoice. Return shipments are made by the Bureau in accordance with its judgment of the best method of shipping unless specific instructions are received. Such instructions should be clearly shown on the purchase order for the test. The Bureau cannot guarantee that instructions printed obscurely on the order will be followed. Parcel post shipments generally will be returned prepaid by the Bureau; but will not be insured.

(3) When a test number has been assigned prior to shipment to the Bureau, this number should be clearly marked on the shipping container. When a test number has not been assigned, an invoice, copy of the purchase order, or letter should be enclosed in the shipment to insure proper identification. The original purchase order should be forwarded to the Bureau.

(4) The risk of loss or damage, either in shipment or in testing, must be assumed by the client. Any arrangements for insurance covering such risk must be made by the client, except that the Bureau will, in other than parcel post shipments, request the carrier to provide insurance coverage for a stated amount for return shipment if this is specified on the face of the purchase order. If transit insurance is carried by the client, this should be stated on the face of the purchase order, and in any case the purchase order should show the value of the equip

ment.

200.105 Identification and operability of devices submitted.

(1) Since the data provided in the Bureau's report is specific to the individual item or piece of apparatus tested, it is essential that this piece be identified uniquely by an appropriate number or symbol. In most cases, the manufacturer's name and serial numbers are used. When such a number is lacking, an alternative identifying mark should be provided. If none is found, the Bureau may apply an appropriate one, usually the Bureau's Test Number, for which an additional charge may be made.

(2) All apparatus submitted for test must be in good operating condition. Repairs and adjustments should be attended to by the client prior to shipment. Apparatus not in good condition cannot be tested, nor can the Bureau undertake the repair or adjustment of any equipment, except by special arrangement. If it is evident that equipment has been abused or has not received proper care, a test ordinarily will not be conducted. If defects are found at the Bureau after a test has begun, this fact will be reported, the test may be terminated and a report issued summarizing such information as has been found, and a fee charged in accordance with the amount of work done.

200.106 Priority and time of completion.

(1) Except for emergency Government work, calibrations and other tests are in general undertaken in the order in which requests are received.

(2) The date at which a test will be completed depends on a number of factors, such as the condition of submitted equipment, set-up time, duration of test run, limitations on available

personnel, occasional large backlogs of work, and grouping of tests of similar devices to les costs. Sometimes repetitive runs are needed to determine reliability of results, or pecu behavior is noted, requiring unusually careful investigation. The Bureau will cooperate w a client to minimize the out-of-use time for his equipment, and will upon request inform him probable starting date and give notice of unexpected delays in completion of the work. E mates of completion dates are therefore provisional.

200.107 Witnessing of operations.

The Bureau welcomes scientists and engineers who may wish to visit its laboratories discuss its methods. However, visitors ordinarily will not be permitted to witness the act carrying out of highly precise measurements because their presence introduces distraction t may lead to errors or delays. This policy may be waived in those cases where the visitor can of service in setting up apparatus of a new or unusual nature, in the case of referee tests, of other cases in which the legal validity of the result may require the presence of duly authori witnesses.

200.108 Report of test.

Results of calibrations and other tests are issued as reports entitled "National Bureau Standards Report of Calibration," "National Bureau of Standards Report of Test," or tional Bureau of Standards Report of Analysis," as appropriate. The report form used car no special significance. Whenever formal certification is required by law, or to meet spe conditions adjudged by the National Bureau of Standards to warrant it, a letter will be provi certifying that the particular item was received and calibrated or tested, and identifying Report containing the results.

200.109 Use of results.

(1) The NBS report of calibration or test contains data which pertain only to the particu device or specimen calibrated or tested. There is no implication that other items of the sa lot or type will show comparable results. However, on the basis of tests on a sample of inst ments or objects drawn from a lot of nominally identical items, in accordance with an appro sampling procedure, the Bureau may declare that the entire lot does or does not meet sta requirements for acceptance.

(2) The results given in the NBS report are limited to the condition of the equipment the time of calibration or test. Clients should not assume that comparable performance will sustained unless suitable precautions are taken in handling and use.

(3) The National Bureau of Standards does not "approve", "recommend", or "endor any proprietary product or material, either as a single item or as a class or group. Res reported by the Bureau shall not be used in advertising or sales promotion, or to indic explicit or implicit endorsement of the product or material by the Bureau.

200.110 Fees.

(1) In accordance with 15 U.S.C. 271-282, fees are charged for tests and calibrations m by the National Bureau of Standards.

(2) This fee schedule is published subject to the above-mentioned basic act which auth izes the Secretary of Commerce, from time to time, to make regulations regarding the paym of fees, the limits of tolerance on standards submitted for verification, and related matters.

The minimum billing charge for any test request accepted by the Bureau is $10, unless otherwise indicated in a particular fee schedule. If apparatus is returned without testing, a minimum charge of $10 may be made to cover handling. Fees for tests include the cost of preparation of an original report. Additional copies ordinarily are not issued to other than the recipient of the original, and are not issued unless the client has shown a technical need for them. Copies of reports requested subsequent to the date of tests will be supplied at cost, with minimum charge of $5. All checks should be made payable to NBS, Department of Commerce.

200.112 Location of laboratories.

The calibrations listed in Parts 202, 203, 204, 205, 206, 208, and 210 of this Subchapter, and the low-frequency electrical calibrations of Sections 201.101 through 201.604 are performed in the laboratories of the National Bureau of Standards, Washington, D.C., 20234. Calibrations of electrical standards in the radio-frequency region (Sections 201.810 through 201.950) are performed by the Radio Standards Laboratory of NBS at Boulder, Colo., 80301. Until July 1966 many of the low-frequency calibration services will also be provided at the NBS Boulder laboratories; subsequently they will be available only in Washington. Inquiries concerning calibrations (giving full details of ranges, frequencies, and electrical burdens), and shipment of apparatus should be directed in accordance with the foregoing. If the apparatus is to be calibrated at both high and low frequencies, arrangements may be initiated with either the Boulder or Washington laboratories. The cost of shipping the apparatus between laboratories will be billed to the client.

Part 201-Electricity

The calibration service covered by this part includes the determinations of the correction for standard electrical and electronic measuring apparatus and their range-extending auxiliaries used at power and audio frequencies (up to 30 kHz (kc/s)), high frequencies (30 kHz to 1,000 MHz (Mc/s)), and microwave frequencies (above 1,000 MHz).

The Bureau does not test, except occasionally for other agencies of the Federal Government, electrical devices or supplies not directly related to the field of measurement. Tests of power transformers, motors, generators, relays, wiring, appliances, etc., should not be requested.

NOTE: Since July 1, 1964, all calibrations by the Electronic Calibration Center of the Radio Standards Laboratory at Boulder, Colo., are normally being performed in a room environment of 40 percent relative humidity (+2%) at a temperature of 23 °C (+2°). Previously the calibrations were performed at 50 percent relative humidity at a temperature of 23 °C.

This environment does not apply to saturated standard cells, resistance standards, and other standards that are calibrated in oil baths at specific temperatures that are usually above room temperature.

Sec.

201.100 General

Resistance Measurements

Precision Wire-Wound Resistance Standards and Apparatus

201.101 Precision standard resistors 201.102 Precision resistance apparatus

201.401 General magnetic measurements; normal induction and hysteresis

201.402 Magnetic materials: alternating-current permeability and core loss 201.403 Magnetic testing apparatus: mutual inductors, search coils, and fluxmeters

201.701 Frequency stability calibration of signal sources, up to 30 kHz (kc/s)

784-291 0-65 ---2

201.810 Rf, rf-d-c voltmeters, and thermal converters in the frequency range of 30 kHz (kc/s) to 1000 MHz (Mc/s) from 0.2 to 300 V

201.811 Rf micropotentiometers, voltmeters, and signal sources from 30 kHz (kc/s) to 1000 MHz (Mc/s), from 1 μV to 0.1 V

201.820 Rf calorimeters, 30 kHz (kc/s) to 500 MHz (Mc/s)

201.821 Continuous wave low-level power measurements of coaxial bolometer units and bolometer-coupler units

201.822 Pulse, peak power measurement, coaxial systems

201.830 Immittance, 30 kHz (kc/s) to 4 GHz (Gc/s)

201.840 Dissipative fixed coaxial attenuators

201.841 Dissipative variable coaxial attenuators

201.842 Waveguide below-cutoff (piston) attenuators

201.843 Coaxial fixed directional couplers

201.844 Coaxial variable directional couplers

201.850 Field strength measurements, 30 Hz (c/s) to 1000 MHz (Mc/s)

201.860 Frequency stability calibration of signal sources, from 30 kHz (kc/s) to 500 MHz (Mc/s)

Microwave Region

201.900 General

201.910 Continuous, low-level power measurement of waveguide bolometer units and bolometer-coupler units

201.911 Continuous low-level power measurement of waveguide dry calorimeters

201.920 Reflection coefficient magnitude measurement on waveguide reflectors (mismatches) 201.930 Frequency measurement on cavity wavemeters

201.940

Attenuation difference measurements on variable attenuators

201.941 Insertion loss measurements on fixed attenuators

201.950 Effective noise temperature measurements on noise sources

Resistance Measurements Involving Precision Wire-Wound Resistors

201.100 General. In general, 201.101 and 201.102 apply only to apparatus embodying the following essential features:

(a) The resistance material should have a low temperature coefficient, should not change its resistance appreciably with time, and for low-valued coils should have a small thermoelectric power against copper.