Page images
PDF
EPUB

C

Research administers a program to provide many types of well-characterized materials that are needed to calibrate a measurement system or to produce scientific data that can be readily referred to a common base. (32 F.R. 21012, Dec. 29, 1967, as amended at 33 F.R. 10627, July 26, 1968] $ 200.106 Critically evaluated data.

Data on the physical properties of the thousands of well-defined substances which are commercially available need to be compiled and evaluated to be useful for reference in engineering design. The Office of Standard Reference Data in the NBS Institute for Basic Standards provides two-way communication with a number of governmental and nongovernmental data centers throughout the country. Its present compilation and dissemination activities cover seven technical areas-nuclear data, atomic and molecular data, solid state data, thermodynamic and transport data, chemical kinetics, colloid and surface properties, and mechanical properties. Accounts of progress appear in the National Standard Reference Data System News (available upon request from the Office of Standard Reference Data) and in the monthly NBS Technical News Bulletin." $ 200.107 Publications.

(a) Changes in services and fees, as published in the supplements to SP 250, appear also in the monthly NBS Technical News Bulletin." The Bulletin also describes recent results of Bureau staff work, lists currently issued publications, and carries sections giving up-to-date detailed information on standards and calibrations, standard reference materials, seminar announcements, conference summaries, and the National Standard Reference Data System. An index to publications by the Bureau authors will be found in Supplements to Special Publication 240, Publications of the National Bureau of Standards. This index covers the publication series of Monographs,' and Technical Notes,' and includes all papers appearing either in the NBS Journal of Research? or in outside technical journals.

(b) U.S. Government Research and Development Reports, a semimonthly announcement journal covering over 1,000

new documents per issue, is sold by the NBS Clearinghouse for Federal Scientific and Technical Information, Springfield, Va. 22151, Other CFSTI series available on subscription include the USGRDR Index, and a Fast Announcement Service which highlights in 57 categories those USGRDR items of particular technological and industrial significance. Any individual item announced is available as paper copy or microfiche. (32 F.R. 21012, Dec. 29, 1967, as amended at 33 F.R. 10627, July 26, 1968] $ 200.108 WWV WWVH WWVB

broadcasts. (a) Technical services. The National Bureau of Standards radio stations WWV at Fort Collins, Colo., and WWVH on the island of Kauai, Hawaii, broadcast a number of technical services continuously night and day. These services are: (1) Standard radio frequencies, 2.5, 5, 10, 15, 20, and 25 MHZ (WWV) and 2.5, 5, 10, 15, and 20 MHz (WWVH); (2) standard time signals; (3) time intervals; (4) UT1 corrections; (5) standard audio frequencies; (6) standard musical pitch; (7) a slow time code; (8) propagation forecasts; (9) geophysical alerts; and (10) storm warnings. The NBS also broadcasts time and frequency signals from its low frequency station, WWVB, also located at Fort Collins, Colo.

(b) Time announcements. Once per minute voice announcements are made from WWV and WWVH. The two stations are distinguished by a female voice from WWVH and a male voice from WWV. The WWVH announcement; occurs first, at 15 seconds before the minute, while the WWV announcement occurs at 712 seconds before the minute. Greenwich mean time (sometimes referred to as UT) is used in these announcements. The actual time scale is known as coordinated universal time (UTC).

(c) Time corrections. The UTC time scale operates on atomic frequency, but by means of step adjustments is made to approximate the astronomical UT1 scale. It may disagree from UT1 by as much as 0.7 second before step adjustments of exactly 1 second are made. These adjustments, or leap seconds are required about once per year and will usually be made on December 31 or June 30. For those who need astronomical time more accurately than 0.7 second, a correction to UTC is encoded by the use of double ticks after the start of each minute. The

1 For sale by the Superintendent of Documents, U.S. Government Printing Ofice, Washington, D.C. 20402.

first through the seventh seconds ticks (h) Propagation forecasts. These ocwill indicate a "plus" correction, and cur in voice at the 14th minute of each from the ninth through the 15th a hour from WWV. They are short-term “minus” correction (the eighth is not forecasts of propagation conditions along used). The correction is determined by North Atlantic paths such as Washingcounting the number of double ticks. For ton, D.C., to London, England, along with example, if the first, second, and third a description of current geomagnetic ticks are doubled, the correction is “plus” activity, and are provided by the Tele0.3 second. If the ninth, 10th, 11th, and communications Services Center, Office 12th ticks are doubled, the correction is of Telecommunications, Boulder, Colo, "minus" 0.4 second.

80302. The format consists of the state(d) Standard time intervals. An audio ment: “The radio propagation quality pulse (5 cycles of 1000 Hz on WWV and forecast at

(one of the following 6 cycles of 1200 Hz on WWVH), resem- times: 0100, 0700, 1300, or 1900 UT) is bling the ticking of a clock, occurs each

.(one of the following adjectives: second of the minute except on the 29th Excellent, very good, good, fair to good, and 59th seconds. Each of these milli- fair, poor to fair, poor, very poor, or usesecond second pulses occur within a 40- less). This statement is followed by: millisecond period, wherein all other "Current geomagnetic activity is modulation (voice or tone) is removed (one of the following characterizations: from the carrier. These pulses begin 10 Quiet, unsettled, or disturbed). milliseconds after the modulation inter- (i) Geophysical alerts. These occur in ruption. A long pulse (0.8 second) marks voice at the 18th minute of each hour the beginning of each minute.

from WWV and at the 45th minute from (e) Standard frequencies. All carrier WWVH. They point out outstanding and audio frequencies occur at their events which are in process, followed by nominal values according to the Inter- a summary of selected solar and geonational System of Units (SI) (not offset physical events in the past 24 hours. as in the past). For periods of 45-second They are provided by the Space Environduration, either 500-Hz or 600-Hz audio ment Laboratory, National Oceanic and tones are broadcast in alternate minutes Atmospheric Administration, Boulder, during most of each hour. A 440-Hz tone, Colo. 80302. the musical pitch A above middle C, is (j) Storm information. These will broadcast once per hour near the begin- cover the waters of the Atlantic from ning of the hour.

WWV and the Pacific from WWVH and (f) Accuracy and stability. The time are given at the 10th and 12th minute and frequency broadcasts are controlled of each hour from WWV and at the 49th by the NBS atomic frequency standards, and 51st minute of each hour from which realize the internationally defined WWVH. Times of issue are 0500, 1100, cesium resonance frequency with an ac- 1600, and 2300 UT from WWV, and 0000, curacy of 2 parts in 1012. The frequencies 0600, 1200, and 1800 UT from WWVH. transmitted by WWV and WWVH are They are prepared by the National held stable to better than +2 parts in Weather Service, Silver Spring, Md. 1011 at all times. Deviations at WWV 20910. are normally less than 1 part in 1012 from (k) “Silentperiods. These are periods day to day. Incremental frequency ad- with no tone modulation during which justments not exceeding 1 part in 104 the carrier, seconds ticks, minute time are made at WWV as necessary. Fre- announcements, and 100 Hz modified quency adjustments made at WWVH do IRIG H time code continue. They occur not exceed 2 parts in 104. Changes in during the 16th through the 20th minute the propagation medium (causing Dop- on WWVH and the 46th through the 50th pler effect, diurnal shifts, etc.) result in minute on WWV. fluctuations in the carrier frequencies as (1) WWVB. This station (antenna coreceived which may be very much ordinates 40°40'28.3'' N., 105°02'39.5" greater than the uncertainties described W.; radiated power 12 kw.) broadcasts on above.

60 kHz. Its time scale is the same as for (g) Slow time code. A modified IRIG WWV and WWVH, and its frequency acH time code occurs continuously on a curacy and stability are the same. Its en100-Hz subcarrier. The format is 1 pulse tire format consists of a 1 pulse per secper second with a 1-minute time frame. ond special binary time code giving minIt gives day of the year, hours, and utes, hours, days, and the correction minutes in binary coded decimal form. between its UTC time scale and UTI

astronomical time. Identification of Standards or the U.S. Government. (A WWVB is made by its unique time code statement to the effect that the National and a 45° carrier phase shift which oc- Bureau of Standards is an agency of the curs for the period between 10 minutes U.S. Government should satisfy other and 15 minutes after each hour. The use- Government agencies with regard to ful coverage area of WWVB is within the compliance with Government regulations continental United States. Propagation and Executive orders.) fluctuations are much less with WWVB (c) A test number will be assigned by than with high-frequency reception, per- the Bureau to each instrument or group mitting frequency comparisons to be of similar instruments or standards when made to a few parts in 104 per day.

the order is accepted. This test number (m) WWVL. This station (antenna co- should be referred to in all subsequent ordinates 40°40'51.3'' N., 105°03'00.0" communications. Also, each instrument W.; radiated power 2 kw.) usually broad- in a group must be uniquely identified, casts on 19.9 and 20.0 kHz. Effective 0000 usually by the manufacturer's name and hours UTC, July 1, 1972, all transmissions instrument serial number. When the sewere curtailed, and depending upon need, rial number is lacking, an alternative this station will broadcast on an experi- identifying mark should be provided. If mental and intermittent basis only.

none is found, the Bureau will mark the (n) Special Publication 236. This pub- piece with an NBS identification number. lication describes in detail the standard If the apparatus submitted has been prefrequency and time service of the Na- viously callbrated by the Bureau, the setional Bureau of Standards. Single copies rial number or identifying mark should may be obtained upon request from the be given on the new order, so that a conNational Bureau of Standards, Boulder, tinuing record of stability history can be Colo. 80302. Quantities may be obtained established. from the Superintendent of Documents, (d) Inquiries for measurement services U.S. Government Printing Office, Wash- related to electrical standards in the raington, D.C. 20402, at 15 cents per copy. dio frequency region (above 30 kHz) or (37 F.R. 28895, Dec. 30, 1972]

to frequency and time standards should

be directed to: $ 200.109 Request procedure.

Coordinator, Calibration Services, Radio (a) A formal purchase order for the

Standards Laboratory, National Bureau of calibration or test should be sent before

Standards, Boulder, Colo. 80302. or at the time the instrument or standard is shipped. This should provide clear

(e) Inquiries for measurement services identification of the apparatus being

other than those noted in paragraph (d) submitted, and give separate instructions

of this section, should be directed to the for return shipment, mailing of report,

NBS address listed in the various sections and billing. If a customer wishes to mini

of SP 250, or to: mize the time during which his equip- Test Administration Unit, National Bureau ment is out of service, he can usually of Standards, Washington, D.C. 20234. arrange to delay shipment until the test

[32 F.R. 21012, Dec. 29, 1967, as amended at is scheduled to start. (See $ 200.111.) Re- 33 F.R. 10627, July 26, 1968] quests from Federal agencies, or from State agencies, for calibrations or tests

$ 200.110 Shipping, insurance, and risk

of loss. on material to be used on private or Federal contract work, should be accompa

(a) Shipment of apparatus to NBS for nied either by purchase order or by let- calibration or other test should be made ter or document authorizing the cost of only after the customer has accepted the the work to be billed to the agency.

estimate of cost and the tentative sched(b) The submission of a purchase uling. Repairs and adjustments on aporder for measurement services under paratus submitted should be attended to this subchapter shall be understood as

by the owner, since NBS will not underconstituting an agreement on the part

take them except by special arrangement. of the customer to be bound by the re

Apparatus not in good condition will not strictions on the use of results as set

be calibrated. If defects are found after forth in section 200.114 below. Accept

calibration has begun, the effort may be ance of purchase orders does not imply terminated, a report issued summarizing acceptance of any provisions set forth in such information as has been found, and the order contrary to the policy, practice, & fee charged in accordance with the or regulations of the National Bureau of amount of work done.

(b) The customer should pack appara- solely by the negligence of Bureau tus sent to NBS so as to minimize the personnel. Ukelihood of damage in shipment and (g) When a test number has been ashandling. Suggestions on packing and signed prior to shipment to NBS, this shipping are made in some sections of number should be clearly marked on SP 250. In every case, the sender should the shipping container. When a test consider the nature of the apparatus, number has not been assigned, an inpack it accordingly, and clearly label voice, copy of the purchase order, or letshipments containing fragile instruments ter should be enclosed in the shipment. or materials, such as glass and the like. to insure proper identification. The The use of “security express” should be original purchase order should be forconsidered in shipping delicate instru- warded as appropriate to: ments.

Test Administration Unit, National Bureau (c) To minimize damage during ship

of Standards, Washington, D.C. 20234. ment resulting from inadequate packing,

or to the use of strong reusable containers is

Coordinator, Calibration Services, Radio recommended. As an aid in preventing

Standards Laboratory, National Bureau of loss of such containers, the customer's

Standards, Boulder, Colo. 80302. name should be legibly and permanently marked on the outside. In order to pro

(h) The calibrations listed in SP long the container's use, the notation

250 are performed at these locations: “REUSABLE CONTAINER, DO NOT

Boulder, Colo., Gaithersburg, Md., and DESTROY” should be marked on the

Washington, D.C. outside.

(1) Calibrations of electrical stand(d) Shipping and insurance coverage

ards and materials in the radio freinstructions should be clearly and legibly

quency region (above 30 kHz) and all shown on the purchase order for the

frequency and time calibrations are percalibration or test. The customer must

formed at Boulder, Colo., and shipments pay shipping charges to and from NBS;

should be addressed to: shipments from NBS will be made col- Coordinator, Calibration Services, Radio lect. The method of return transporta- Standards Laboratory, National Bureau of tion should be stated, and it is recom- Standards, Boulder, Colo. 80302. mended that return shipments be in

If apparatus for radio frequency is also sured, since NBS will not assume liability

to be given incidental low-frequency for their loss or damage. For long-dis

calibration (below 30 kHz), this may be tance shipping it is found that air express done at Boulder, but if a complete range and air freight provide an advantage in

of low-frequency calibrations are needed, reduction of time in transit. If return

the instrument should be sent to: shipment by parcel post is requested or is a suitable mode of transportation,

National Bureau of Standards, Route 708

and Quince Orchard Rd., Gaithersburg. shipments will be prepaid by NBS, but

Md. 20706. without covering insurance. When no shipping or insurance instructions are (2) Calibrations listed in SP 250 furnished, return shipment will be made other than those noted in paragraph by common carrier collect, but uninsured. (1) above, of this section, are performed

(e) NBS will not be responsible for in the Bureau's laboratories at either the risk of loss or damage to any item Gaithersburg, Md., or Washington, D.C. during shipment to or from the Bureau.

For shipments which are heavy (in exAny arrangements for insurance cover

cess of 100 lbs.) or bulky (a combined ing this risk must be made by the customer. Return shipment will be made

girth in excess of 27 cu. ft.), request &

shipping address from: by the Bureau as indicated in paragraph (d) of this section. The purchase order Test Administration Unit, National Bureau should always show the value of the of Standards, Washington, D.C. 20234. equipment, and if transit insurance is

Items other than heavy or bulky shipcarried by the customer, this fact should ments that are sent by common carbe stated.

rier, should be addressed to: (f) The risk of loss or damage in han

National Bureau of Standards, Route 705 dling or testing of any item by NBS

and Quince Orchard Rd., Gaithersburg, must be assumed by the customer, ex- Md. 20706. cept when it is determined by the Bureau (32 F.R. 21012, Dec. 29, 1967, as amended at that such loss or damage was occasioned 33 F.R. 10627, July 26, 1968]

8 200.111 Priorities and time of comple- adjudged by the National Bureau of tion.

Standards to warrant it, a letter will be Schedule work assignments for call

provided certifying that the particular brations and other tests will generally

item was received and callbrated or be made in the order in which confirmed

tested, and identifying the report conrequests are received. However, Govern

taining the results. ment work may be given priority. On the

(b) NBS reports of callbration generregular services, the workload is usually

ally include in sentence form a statement such that the turn-around interval, be

of the uncertainty attached to the tween the date a customer's apparatus is

numerical values reported. Limits of received and the date it is prepared for

uncertainty usually comprise (1) an estireturn shipment, will be not more than

mate of systematic error, plus (1) a value 45 days. Some types of instruments may

of imprecision. require considerably longer, particularly

(1) Often the systematic error estiif their abnormal behavior requires re

mate is based on experience or judgment. runs to check reliability. Others can be

Sometimes it is an explicit combination calibrated and returned within 10 days.

of a number of elemental systematic Special tests, such as the "Z" items

errors. Sometimes the value can be listed in SP 250 require individual

checked by using two completely differscheduling. The customer who can spare

ent physical phenomena, types of standhis instrument for only a short time can

ard, or measurement techniques. usually arrange by letter or phone call

(2) Imprecision is preferably expressed for shipping it to the Bureau just as his

as three times the standard deviation of assigned starting date approaches. A

a single determination, or three times the notice will be sent acknowledging receipt

standard error of the arithmetic mean of of the customer's standard and/or pur

n determinations, either being a canonchase order. If both a confirmed pur

ical value for the measurement process chase order (or equivalent) and the ap

based on considerable recent experience. paratus have been received, estimates of

When extended experience is lacking, the a completion date and a calibration fee

terms “computed standard deviation” or will be sent upon request.

"computed standard error" should be

used. (32 F.R. 21012, Dec. 29, 1967, as amended at

(3) A laboratory using NBS results to 33 F.R. 10627, July 26, 1968]

estimate the uncertainty attached to its $ 200.112 Witnessing of operations. own work may equate its own systematic

The Bureau welcomes scientists and error to the NBS quoted limit of uncerengineers who may wish to visit its lab- tainty, as a minimum. The imprecision oratories and discuss its methods. Ordi- of its own work is best evaluated by callnarily visitors will not be permitted to bration records extended over considerwitness the actual carrying out of highly

able periods of time, with repetition of its precise measurements because their pres

specified calibration procedure and ence introduces distraction that may assurance that its measurement process lead to errors or delays. This policy may

is in statistical control. For further inforbe waived in those cases where the visitor

mation see: can be of service in setting up apparatus

(1) Youden, W. J., Uncertainties in of a new or unusual nature, in the case

Calibration. IRE Trans., vol. I-11, Nos. 3 of referee tests, or in other cases in which

and 4, p. 133 (December 1962). the legal validity of the result may

(ii) Eisenhart, Churchill, Realistic require the presence of duly authorized

Evaluation of the Precision and Accuwitnesses.

racy of Instrument Calibration Systems.

NBS J. Res., vol. 67C, No. 2, p. 161 (April$ 200.113 Reports.

June 1962). (a) Results of calibrations and other (iii) Natrella, M. G., Experimental tests are issued to the customer as formal Statistics. NBS Handbook 91, Aug. 1, reports entitled, “National Bureau of 1963, ch. 23. Standards Report of Calibration," (iv) Wildhack, W. A., H. L. Mason, and “National Bureau of Standards Report of R. C. Powell, Accuracy in Measurements Test,” or “National Bureau of Standards and Calibrations, 1965. NBS Technical Report of Analysis," as appropriate. Note No. 262. (Shows the general status Copies are not supplied to other parties. of NBS accuracy limits as of June 1965.) Whenever formal certification is required (v) Wildhack, W. A., H. L. Mason, R. S. by law, or to meet special conditions Powers, Jr., Accuracy Charts for RF

« PreviousContinue »