ALS-U Units Policy and Units Definition - AL-1009-9880.pdf

Advanced Light Source Upgrade Project Lawrence Berkeley National Laboratory

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ALS-U Units Policy and Units Definition

Eric S. Buice Release Date: Apr 5 2021 1:54:22 PM PDT

Document Number: AL-1009-9880 Revision: B

Document Status: Released Document Type: Engineering Note

Category Code: AL8600

ALS-U - SYSTEMS ENGINEERING

GENERAL

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TABLE OF CONTENTS

1 Revision History

2 Approvals

3 Abbreviations and Acronyms

4 Introduction

5 Policy Applicable to all Federal Agencies

6 ALS-U Policy on the Use of the SI System

7 Defining SI Base and Derived Units

7.1 SI Base Units

7.2 SI Derived Units

8 Additional Acceptable Units for use within ALS-U

9 Definition of Fundamental Physical Constants

10 Writing Convention for Unit Symbols

10.1 Unit Symbol Typeface

10.2 Unit Symbol Plurals

10.3 Unit Symbol Punctuation

10.4 Unit Symbol Obtained by Multiplication and Division

10.5 Units Symbol Associated with the Nominal Value having an Uncertainty Value

10.6 Unit Symbol with Prefix

10.7 Unit Symbol with Numeric Value

11 Writing Convention for Spelling Unit Names

11.1 Capitalization

11.2 Plurals

11.3 Units with Prefixes

11.4 Spelling Unit Names after Multiplication, Division and Raised to Powers

12 Exceptions to ALS-U Units Policy and Deviation Request Procedure

13 Applicable Documents

14 References

1 REVISION HISTORY

Rev. Rev. Author Description of Change A Eric Buice First release

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B Ken Chow Updated section 12: changed section title, included exception for anchoring hardware, updated description of deviation request procedure.

Updated approver list.

Changed references to Technical Integration Team to instead be to Technical Review Board.

Changed title to “ALS-U Units Policy and Units Definition”.

Updated footer statement about officially released versions of LBNL documents.

2 APPROVALS

The following individual(s) shall approve this document:

Approver Project Role Roberta Leftwich-Vann Project Manager Ken Chow Chief Engineer Christoph Steier Accelerator Systems Manager Jorge Pearce Accelerator Systems Deputy Elaine DiMasi Beamlines and Optical Systems Manager Daniela Leitner Removal and Installation Manager Windchill Approved / Concurred By wjpearce,rleftwichvann,CSteier,edimasi,KPChow,DLeitner

3 ABBREVIATIONS AND ACRONYMS

ALS Advanced Light Source ALS-U Advanced Light Source Upgrade Project CODATA Committee on Data for Science and Technology DCC Document Control Center LBNL Lawrence Berkeley National Laboratory NIST National Institute of Standards and Technology PL Public Law SI International System of Units TRB Technical Review Board

4 INTRODUCTION

This document describes the unit convention and fundamental physical constants that shall be adopted within ALS-U. Also described in this document are the rules and style convention of units. Unit definition is based on the guidelines document provided by the National Institute for Standards and Technology (NIST), see Thompson and Taylor 2008 (NOTE: deviations from the NIST guidelines are made within this document).

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5 POLICY APPLICABLE TO ALL FEDERAL AGENCIES

Public Law (PL) 100-418 states

“the metric system of measurement as the preferred system of weights and measures for the United States…” and requires

“each Federal agency, by a date certain and to the extent economically feasible by the end of fiscal year 1992, use the metric system of measurement in its procurements, grants, and other business-related activities, except to the extent that such use is impractical or is likely to cause significant inefficiencies or loss of markets for the United States…”

This was further emphasized by updating the definition of the metric system with the America COMPETES Act (PL 110-69) in 2007 stating

“The metric system of measurement shall be defined as the International System of Units as established in 1960, and subsequently maintained, by the General Conference of Weights and Measures, and as interpreted or modified for the United States by the Secretary of Commerce.” (Thompson and Taylor, 2008)

6 ALS-U POLICY ON THE USE OF THE SI SYSTEM

ALS-U shall adapt the International System of Units (SI) as the official system of units.

All documents generated shall use the SI system. It is preferred to use the SI base units, but SI derived units are also considered acceptable. SI base units and SI derived units are described in subsequent sections.

If it is necessary to use units other than SI units due to common usage or practice, then the SI units shall be listed first, followed by the non-SI unit in either parenthesis or brackets. However, it shall be understood and clearly identified that the first listed SI unit is the defining measure. This may be of particular interest for dimensioning drawings as many machine shops in the USA primarily use English units (SI unit would still be the defining measure where the English unit is used as reference only).

Exception to the ALS-U units policy and this guide is described in Section 12 of this document.

7 DEFINING SI BASE AND DERIVED UNITS

7.1 SI Base Units

The SI system defines seven base units. These are listed in Table 7.1.

Table 7.1: List of the seven SI base units.

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Base Quantity Name Symbol Amount of substance mole mol Electric current ampere A Length meter m Luminous intensity candela cd Mass kilogram kg Thermodynamic Temperature kelvin K Time second s

7.2 SI Derived Units

Utilizing the SI base units it is possible to derive additional units that are referred to as SI derived units. Several examples of SI derived units are listed in Table 7.2. The use of any SI derived unit shall be considered acceptable within the ALS-U project. Figure 7.1 shows a chart indicating the relationship between SI base units and SI derived units.

Table 7.2: Examples of SI derived units.

Derived Quantity Name Symbol Expression in SI Base Units

Area square meter m2 m2 Velocity meter per second m s⁄ m s-1 Acceleration meter per second squared m s2⁄ m s-2 Force Newton N kg m s−2 Power Watt W kg m2 s-2 Plane angle radian rad m m-1 Pressure pascal Pa kg m-1 s-2 Energy joule J kg m2 s-2 Celsius temperature degree Celsius ℃ K Electric charge coulomb C A s Frequency Hertz Hz s−1 Magnetic flux Tesla T kg A-1 s-2 Voltage Volt V kg m2 s-3 A-1 Resistance Ohm Ω kg m2 s-3 A-2 Capacitance farad F s4 A2 kg-1 m-2

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Figure 7.1: Chart showing the relationship between SI base units and SI derived units (taken from Thompson and Taylor 2008).

8 ADDITIONAL ACCEPTABLE UNITS FOR USE WITHIN ALS-U

This section lists units that are considered acceptable to be used within the ALS-U project even if they are considered outside the SI system and are listed in Table 8.1. Any additional units that are desired for project-wide use on ALS-U shall be submitted to the Technical Review Board (TRB) prior to use for full evaluation, see section “Exceptions to ALS-U Units Policy and Deviation Request Procedure” for additional information.

Table 8.1: Acceptable units that can be used within the ALS-U project.

Name Symbol

Minute (time) min Hour (time) h Day (time) D Degree (angle) ° Minute (angle) ' Second (angle) " Liter L Decibel dB Electron volt eV Unified atomic mass unit u Torr (pressure) Torr

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9 DEFINITION OF FUNDAMENTAL PHYSICAL CONSTANTS

Information provided by CODATA 2014 (AL-1010-9342) shall be used to define all fundamental physical constants. Table 9.1 shows an excerpt of the fundamental physical constants as stated in CODATA 2014.

Table 9.1: Excerpt of fundamental constants as stated in CODATA 2014, see AL-1010- 9342 for full list.

Quantity Symbol Numerical value Unit Relative standard uncertainty Speed of light in vacuum c 299792458 m s-2 exact Magnetic constant 𝜇𝜇0 4𝜋𝜋 × 10−7 N A-2 exact Electric constant (𝜇𝜇0−1 𝑐𝑐−2) 𝜖𝜖0 8.854187817 … × 10−12 F m-1 exact Planck constant h 6.626070040(81) × 10−34 J s 1.2 × 10−8 Elementary charge e 1.6021766208(98) × 10−19 C 6.1 × 10−9 Electron mass 𝑚𝑚𝑒𝑒 9.10938356(11) × 10−31 kg 1.2 × 10−8 Avogadro constant 𝑁𝑁𝐴𝐴 6.022140857(74) × 1023 mol-1 1.2 × 10−8 Electron volt eV 1.6021766208(98) × 10−19 J 6.1 × 10−9 Unified atomic mass u 1.660539040(20) × 10−27 kg 1.2 × 10−8

10 WRITING CONVENTION FOR UNIT SYMBOLS

The following subsections are rules and style conventions related to unit symbols that shall be used when generating documents.

10.1 Unit Symbol Typeface

Unit symbols shall be upright (not italic).

Example: 𝑀𝑀 = 9.81 N m (Note that M is italic as it is part of the equation whereas the unit Newton meter is written upright.)

10.2 Unit Symbol Plurals

A unit symbol shall be written in singular form.

Example: 𝑚𝑚 = 24 kg; Unacceptable: 𝑚𝑚 = 24 kgs

10.3 Unit Symbol Punctuation

A period is only applicable if the symbol is at the end of a sentence. A period shall never be placed after a unit symbol if it is not at the end of a sentence.

Example: “The second rock has a mass of 20 kg.” or “The second rock is 5 kg heavier than the first rock.”

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10.4 Unit Symbol Obtained by Multiplication and Division

If two unit symbols are multiplied then they shall be separated by a space.

Example: m s (meter second); Unacceptable: m-s, ms (this could be interpreted as millisecond)

If two unit symbols are divided then the units can either be separated by “/”, horizontal line or space with the dividing unit symbol having a negative exponent. The use of a horizontal line or negative exponent is the preferred method as it avoids confusion. A “/” may only be used once in a single line.

Example: kg A-1 s-2, kg A s2, or kg/(A s2); Unacceptable: kg A s2⁄⁄

10.5 Units Symbol Associated with the Nominal Value having an Uncertainty Value

A nominal value and the associated uncertainty to the nominal value shall either have a unit symbol directly after the nominal and uncertainty value or placing the nominal and uncertainty value inside a parenthesis followed by the unit symbol.

Example: 5 N ± 1 N, (5 ± 1) N; Unacceptable: 5 ± 1 N

10.6 Unit Symbol with Prefix

No space shall be placed between a prefix and unit symbol. The use of two prefixes for a single unit symbol is unacceptable.

Example: mm (millimeter), kg (kilogram)

Example: nm (nanometer); Unacceptable: mµm (millimicrometer)

10.7 Unit Symbol with Numeric Value

A single space shall be placed between the numeric value and unit symbol.

Example: 10 kg, 35 N; Unacceptable: 10kg, 35N, 10-kg, 35-N

11 WRITING CONVENTION FOR SPELLING UNIT NAMES

The following subsections are rules and style conventions related to the spelling of units.

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11.1 Capitalization

Unit names that are spelled out are to be treated as a noun. Units that are named after a person or are at the beginning of a sentence shall be capitalized.

Example: The unit ‘meter’, when spelled out is not capitalized.

11.2 Plurals

English grammar rule is to be followed if a unit name needs to be plural.

11.3 Units with Prefixes

Units that use prefixes, such as milli or kilo, are to be spelled out with the unit as a single word. No spaces or hyphens shall be used between the prefix and unit name.

Example: millimeter, kilogram

11.4 Spelling Unit Names after Multiplication, Division and Raised to Powers

If units are multiplied, then the unit names are separated by a space.

Example: Newton meter (N m)

If units are divided, then the unit names are separated with the word “per”.

Example: meter per second (m s-1)

If the unit is raised to a power, then the unit name is spelled with a modifier such as “squared” or “cubed”.

Example: cubic meter (m3)

12 EXCEPTIONS TO ALS-U UNITS POLICY AND DEVIATION REQUEST

PROCEDURE

12.1 Anchoring Hardware and Tools

Seismic anchoring of ALS-U equipment is standardized to exclusively use hardware and tooling based on imperial units. A weighing of overall cost, benefits, and risks across the project indicates an overall benefit to standardizing on imperial anchors and tooling.

Additional costs arise due to the need to manage/maintain a dual set of associated hardware, such as installation jigs, drillbits, and testing hardware, to support a mix of anchors in both imperial and SI varieties. Anchoring contractors are not tooled up to

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All officially released LBNL documents are watermarked and contain LBNL Document handle anchors based of an SI unit variety. The risk of human errors increases as well with anchor sets that are a mix of metric and imperial for different components.

The standardization of using imperial-units anchors for ALS-U applies to the interface between anchored equipment and concrete floors, walls, and tunnel shielding blocks in the ALS facility (B6, B15, B80). It only applies to the first connection point between the concrete and the equipment, as shown in Figure 12.1. Subsequent connection points, such as between stands and baseplates, or between equipment and support stands, follow the standard ALS-U units policy.

The imperial-units exception applies to epoxy-/adhesively-set anchors, such as threaded anchor rods, rebar, internally threaded inserts, and conical anchor rods, and also to mechanical anchors, such as expansion anchors, undercut anchors, screw anchors, flush anchors, and wedge anchors. It also applies to other associated hardware such as nuts, washers, and bolts (for internally-threaded inserts).

The imperial-units exception subsequently applies to anchoring tools, such as hammer drill bits, hollow vacuum drill bits, and diamond core drill bits. Process tools such as drill stops/guides, setting tools, hole roughening & cleaning tools, anchor testers, and anchor removal tools, are also included.

Since the anchors are standardized to imperial sizes, the dimensions of associated anchor holes and equipment clearance holes shall also use imperial sizes. To maintain consistency with other ALS-U project documents, list the SI units first, followed by the imperial unit in either parentheses or brackets.

Several exclusions exist for the standard use of imperial-units anchors project-wide.

These include:

• Re-anchoring or modification of equipment that have existing metric anchors.

• Anchorage of equipment where SI-units anchors are required, due to the dimensions of the equipment’s anchoring features.

• Any situation where the Authority Having Jurisdiction (AHJ) calls specifically for metric anchors instead of imperial anchors.

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Figure 12.1: Imperial anchors exception applies to the first connection point between the concrete and the equipment (shown in green). Subsequent connection points (shown in red) follow the standard SI units policy.

12.2 Deviation Request Procedure

Exceptions to the ALS-U units policy require approval from the Technical Review Board

(TRB). See ALS-U Configuration Management Plan, AL-1115-6080, for a description of the TRB. Requests for exceptions shall be made to the TRB via a brief presentation at a TRB meeting or other means. The TRB shall evaluate and decide upon granting the exception. This section shall be revised as exceptions are granted by the TRB.

13 APPLICABLE DOCUMENTS

This section identifies applicable documents that are considered to be a part of this document. All information contained in an applicable document shall be valid to the full extent, unless specifically noted within this document. Applicable documents shall be obtained from the LBNL Document Control Center (DCC).

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Document Number Title AL-1010-9342 CODATA recommended values of the fundamental physical constants

14 REFERENCES

Documents listed in this section are considered reference documents that can be used to better describe, clarify intent, or provide information where the information was obtained from.

AL-1115-6080, ALS-U Configuration Management Plan.

Mohr, P. J., Newell, D. B., Taylor, B. N. 2016. CODATA recommended values of the fundamental physical constants: 2014. Rev Mod Phys. 88. 035009.

Thompson, A., Taylor, B. N. 2008. Guide for the use of the International System of Units (SI). NIST Special Publication 811.