Tiêu chuẩn iso 12917 1 2017

7 Cal bration proc edures The calbration proc d r s for calbration of horizontal cy lin rical tan s shal be pe formed as spe if ied in 7.2 ext ernal measur ment an 7.3 int ernal measur

P etroleum and liquid petr oleum

Part 1:

Pétrole et produits p troliers liquide s — Ja gea e des réserv irs

c ylindrique s h rizo ta x —

Partie 1: Méth de s ma ue lle s

S con edition

2 17-0

Refer ence n mb r

COPYRIGHT PROTECTED DOCUMENT

© ISO 2017, P blshed in Sw itz rlan

A ll rig hts r eserved Unles otherw ise spe ified, nopar of this p blc tion ma y be r epr od c d or utilz d otherw ise in an form

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written permis ion Permis ion c n be req esed from either ISO at the ad r es below or ISO’s member bod y in the c u try of

F reword v

Introduction vi

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 Precautions 1

4.1 General 1

4.2 Inte nal method 2

4.3 Ex te nal method 2

5 Equipment 2

5.1 Eq ipment as used in ISO 7 0 -1 2

5.2 Telesco ic rod 2

5.3 Dis anc mete 2

5.4 Levele 2

6 General r equirements 2

7 Calbratio proc edures 3

7.1 General 3

7.2 Measur ement of circumfer enc s — Exte nal 3

7.2.1 Intr oduction 3

7.2.2 General 3

7.2.3 Repetition of measurement 4

7.3 Measur ement of circumfer enc s — Inte nal 5

7.3.1 Ove view 5

7.3.2 General 5

7.4 Measur ement of leng ths 5

7.4.1 Method 5

7.4.2 Leng th of horizontal cyln e 6

7.4.3 Leng ths of seg ment 6

7.4.4 Leng ths of heads 7

7.4.5 Gaug e leng ths 7

7.4.6 Measur ement/calculations of r adi of the heads 7

7.5 Tan tilt 7

7.6 Plate thick es 8

7.7 Referenc height 8

7.8 Deadwo d 8

7.9 Measur ement of temperatur e and pres ur e 8

8 Re-calbration 8

9 Des ripti ve data 9

10 Computatio of tank capacity table 10

1 1 General rules 1

1 2 A ccuracy of v lume 1

1 2.1 General 1

1 2.2 C lculation paramete s 1

1 2.3 Volume calculation 1

1 3 Corr ections of v lume of tan table 2

1 3.1 General 2

1 3.2 Wor king pr es ur e 2

1 3.3 Tank-shel temperatur e 24

A nne x A (informative) C mp tation of tank capacity tables based on indi vidual

seg ment dimensions 26

A nne x B (informative)Calculation e xamples 29

A nne x C (informative) Calbratio u c ertainties 39

Biblog raph y 46

ISO (he Int ernational Org nization for Stan ardization) is a worldwide fede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Standards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a l shed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that ome of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such pat ent right Detais of

any p t ent right identif ied d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the v lu tary natur of s an ards, the meaning of ISO spe ific t erms an

ex r s ions r lat ed t o conformity as es ment, as wel as information a out ISO’s adhe enc t o the

World Trade Org nization (WTO) principles in the Te hnical Bar ie s t o Trade (TBT) se the folowing

URL: www iso org iso/ for word html

This document was pr p r d b Te hnical C mmitt ee ISO/TC 2 , Petroleum produc ts a d lu ric ants ,

Subcommitt ee SC2, Meas ur ment o petroleuma d r lated produc ts

This se on edition canc ls an r plac s the f irs edition (ISO 1 9 7-1:2 0 ), w hich has be n t ech icaly

r vised with the folowing chang es

— The t otal length of the tanks has be n l mit ed and also only the cal bration via ISO 7 0 -1 is desc ibed

in orde t o impro e pr cision

— Mos of the f igur s ha e be n impro ed in orde t o furthe clarify the measur ment proc d r s

These, in turn, ha e be n desc ibed mor lo icaly an in a mor useful orde F or ins anc , tank

shel measur ment ar no long er desc ibed separat ely an the forme Annex on “ it” has be n

incorp rat ed in the t ext

— A new annex on calbration unc rtainties has be n ad ed

— Cor e tion for tank ti t is now calculat ed rathe than r ad from a f igur

It also incorporat esthe Te h ical Cor ig en um ISO 1 9 7-1:2 0 /Cor 1:2 0

A l s of part in the ISO 1 9 7 se ies can be fou d on the ISO websit e

This document forms p rt of a se ies on tan calbration methods In somecountries, some or al of the

it ems co e ed b this document ar subje t t o local r gulations The att ention of the use is drawn t o

the fact that it isp s ible that dife enc s exis betwe n this document an those r gulations

P etroleum and liquid petr oleum products — Calibration of

The methods in this document ar a plca let o insulat ed an non-insulat ed tanks, eithe w hen they ar

a o e-groun or u de grou d The methods ar a plca le t o pr s uriz d tanks an t o b th k

uckle-dish-en an flat-en cy lin rical tan s as wel as el ptical an sphe ical head tan s

This document is a plca le t o tan s incl ned from the horizontal, pro ided a cor e tion is a pl ed for

the measur d tit

Although this document does not impose any lmit on the ma im um tan diameter an ma im um tan

tit to which this document is a pplca le, the pra ctical lmit would be a out 4 m in diameter an 1 ° in tit

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 7 0 -1:2 0 , Petroleum a d liquid petroleum produc ts — Calbration o vertic al cylndric al ta k s —

Part 1: Stra pin meth d

3 Terms and definitions

No t erms an def initions ar lst ed in this document

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

4 Precautions

The g ene al an safety pr ca utions spe ified in ISO 7 0 -1 shal be a pled

4.2 Internal method

Befor a tan w hich is t o be cal brat ed is ent er d, a safe-entry c rtif icat e shal be o tained Al lnes

ent ering the tank shal be discon e t ed an blanked

NOTE T e at ention of the user is drawn to the pos ible e istence of local re ulations re arding the

safe-entry certif icate an entry int o tan s, which have contained le ded fuels

Eq ipment used in the cal bration of horizontal tan s shal conform t o the spe ifications laid down in

ISO 7 07-1 Al eq ipment shal be trac a le t o a r fe enc s an ard

NOTE T e eq ipment req ired to car y out the calibration is depen ent on the method t o b employed T is

document uses t ech iq es an eq ipment des rib d in ISO 75 7-1

5.2 Telesc opic r od

F or the int ernal method, in ad ition t o the eq ipment mentioned in 5.1, a t elesco ic rod ma be used

This t elesco ic rod shal ha e a scale ca a le of being r ad t o 1 mm, an shal be calbrat ed with an

unc rtainty of les than 1mm

5.3 Distanc e meter

F or the int ernal method, as an alt ernative t o a t elesco ic rod, a laser-b sed dis anc met er ma be used

The dis anc met er ma also be used in measur ment of tank tit This dis anc met er shal ha e a scale

ca a le of being r ad t o 1 mm, an shal be calbrat ed with an u c rtainty of les than 1 mm

5.4 Level er

Level-measuring ins rument used t o det ermine vertical dis anc s betwe n p irs of p int It can be

b sed on eithe me hanical or o tical measur ment

Ex mple R otating optical/laser instrument that esta lishes horizontal reference line /plane, with a

mechanical height-me suring device

6.1 The tan shal be fi ed to its normal wor king ca acity an wor king pr es ure at leas onc an

alowed to s an whie ful for at leas 24 h prior to emptying an pr ep ring it for calbr ation

NOTE The hydrostatic test ap lied t o new or repaired tan s wil satisfy this req irement when ad itional

pres ure tests have b en car ied out

6.2 The folowing p ramete s shal be dete mined:

— t empe atur ;

— pr s ur ;

— position of g ug e p int, r fe enc height an height of the dip plat e, if the e is one

7 Cal bration proc edures

The calbration proc d r s for calbration of horizontal cy lin rical tan s shal be pe formed as

spe if ied in 7.2 (ext ernal measur ment ) an 7.3 ( int ernal measur ment ) The r main e of Clause 7

a ples t o b th ext ernal an int ernal measur ment

F or b th methods, measur ment shal be taken at arou d 1 4 an 3 4 of the length of each segment in

ac ordanc with Figur 1

7.2 Measurement of circumferenc es — Ex ternal

7.2.1 Intr oductio

Ext ernal measur ment ma be ex ecut ed with any depth of lq id an lq id pr s ur in the tank The

t empe atur an pr s ur of the lq id at the time of cal bration shal be r corded

7.2.2 General

F or the measur ment proc d r s, a cir umfe ential ta e of suff icient length t o complet ely encir le the

tan should be used an measur ment of the t otal cir umfe enc shal be taken

a) In al cases, the ta e t o be used should be a pled t o the tan surfac at he pr sc ibed locationsb

the wra arou d proc d r ; i.e the r q ir d length of ta e should be a pled in a slack con ition,

positioned, and tight ened b the a plcation of the pro e t ension

As in icat ed in Figur 1, s ra ping should be un e taken aroun 1 4 an 3 4 of the segment length

b) In the case in w hich the cir umfe ential measuring ta e is in contact with the tank surfac at al

point along it p th, cir umfe ential measur ment should be made an che ked in ac ordanc

with the r lev nt proc d r given in ISO 7 07-1

c) If the cir umfe ential measuring ta e is not in contact with the tank surfac , cor e tions should be

made for in ivid al o s ructions as spe if ied in ISO 7 0 -1

3/4 (W

i)

he d leng th (b ttom of tank)

W totaltan leng th

Figure 1 — Me surements of the diameters/cir umferences

7.2.3 Repetitio of me surements

Aft er the cir umfe enc has be n measur d, the t ension shal be r leased an the ta e brought a ain t o

the r q ir d level an t ension The r adingsshal then be r peat ed an r corded

Take multiple measur ment of the cir umfe enc Inves ig t e an , if ne es ary, r mo e the pe c ived

outle s If the firs thr e conse utive measur ment a r e within ± mm, take their a e ag e as the

cir umfe enc an their s an ard deviation as the s an ard unc rtainty If they do not a r e within

this t ole anc , r peat hemeasur ment u ti two s an ard deviations of the mean of al measur ment

is les than the half of this t ole anc Use the a e ag e as the measur d cir umfe enc and the s an ard

deviation asthe s an ard unc rtainty

7.3 Measurement of circumferenc es — Internal

7.3.1 Over view

Int ernal measur ment shal be pe formed with the tank empty, at ambient t empe atur an with no

pr s ur in the tan In-tan t empe atur at thetime of calbration shal ber corded The e isno ne d

t o do pr s ur r cording or cor e tions u les the r fe enc con itions for the tank r q ir it

7.3.2 General

F or the measur ment proc d r s, a t elesco ic rod (5.2) of suff icient length t o complet ely measur the

int ernal diamet er of the tank or the dis anc met er (5.3) shal be used

NOTE Distance meter is normal y prefera le for tan s with diameter ex ce ding 3 m

The t elesco ic rod or the dis anc met er shal be a pled t o the tank at the pr sc ibed locations, at four

p sitions, eq al y divided aroun the cir umfe enc in ac ordanc with Figur 2 The t elesco ic rod

should be at a 9 ° angle at each t ouch p int The a e ag e of these four measur ment shal be r corded

as diamet er at this particular location within this p rticular segment Car should be taken t o ensur

that the measur d diamet er is in e d the minimum v lue in longitu inal dir ction an ma imum v lue

in cir umfe ential dir ction

Figure 2 — Internal me surements of diameter

7.4 Measurements of leng ths

7.4.1 Method

Dis anc betwe n a single r fe enc point an the extr me point of tank b dy as wel as those of b th

heads shal be measur d in ac ordanc with Figur 3

NOTE T ese me surements can b performed using a tape or distance met er, with help of a line or ruler

The r fe enc p int ma be anyw he e on the b dy of the tank It pr fe r d location is on one of the

welds joining the en s t o the b dy of the tan , pro iding that the ear no o s acles

R epeat al measur ment u ti two conse utive r adings a r e within a t ole anc of ± mm

Conside ing the u c rtain width an location of the welds, the measur ment of length should

pr fe a ly be done t o point made on the shel, on or close t o the welds

Figure 3 — Me surements of the lengths

7.4.2 Leng th of hor izo tal cylnder

The length of the horizontal tan (cy lin rical p rt) is measur d between the extr me welds of the

extr me segment (k uckle welds) at two locations at o p sit e sides of the tan , pr fe a ly w he e

the e ar no o s ructions ( e Figur 3) Take multiple measur ment at each location using measuring

ta e or dis anc met er If the f irs thr e conse utive measur ment a r e within ± mm, take their

a e ag e as the tank length an their s an ard deviation as the s an ard unc rtainty If they do not

a r e within this t ole anc , r peat the measur ment u ti two s an ard deviations of the mean of al

measur ment is les than the half of this t ole anc Use the a e ag e as the measur d tan length an

the s an ard deviation as it s an ard unc rtainty

7.4.3 Leng ths of seg ments

Themeasur ment ma bedone int ernal y or ext ernaly

± mm, take their a e ag e as the length of the segment an their s an ard deviation as the s an ard

unc rtainty If they do not a r e within thist ole anc , r peat the measur ment u ti they do

Lengths of the s raight flang es conne ting the extr me segment t o the heads should be measur d the

samewa

Comp r the sum of lengths of al segment inclu ing the s raight flang es t o the t otal length of the tank

an modify length of al segment b their ratio so that the sum of the lengths of the segment is the

sameas the length of the tan

7.4.4 Leng ths of he ds

Length of each head shal be measur d as dis anc betwe n the en plane (mark at the en weld of the

cy lin e )an the en p int of the head ( e Figur 3)

7.4.5 Gaug e leng ths

Ga ug e length is not measur d but defined b the cal brat or within the l mit of the up e an lowe

en s of the g ug e hat ch ( e Figur 3)

7.4.6 Me sur ement/calculatio s of radi of the he ds

To measur the radi using traditional means is diff icult an e rors ( in cm) ma r sult The tan heads

ar usualy made using pr -man factur d forms, r sulting in wel -def ined an r petitive sha es

Head radi should be pr fe a ly o tained from man factur r’ s drawings If these ar not a ai a le,

othe methods should be used

— Using a theodol t e t o prod c a thr e-dimensional sha e of the head could be the bes o tion

— The radi of the heads can be det ermined from the measur d lengths in combination with diamet ers

of the extr me segment of the tan b dy, using the exis ing man factur rs’ s an ards

— The e ar national s andards that define the radi of k uckle an dish for the given radius of the

tan b dy The s an ard, w hich the tan end comples with, can be det ermined b comp ring it

sha e t o pr -fa ricat ed t emplat es that conform t o the s andard Onc this is done, the radi can be

r ad from ta les within the s an ard for the given length of the head an tank diamet er R elev nt

s an ards ar NF E 8 -1 0 t o 1 4 (Fr nch), SMS 48 an 48 ( Swedish) and NEN3 5 (Dut ch)

Radi of the k uckle ar r g rded as imp s ible t o measur They should be o tained from

man factur r’s drawings

NOTE Variations in he d radi have very lit le impact on the me sured volumes

7.5 Tank ti t

If the tan segment v ry in diamet er an in the al gnment of their ve tical ax es, the tit should be

measur d an calculat ed from multiple measur ment of ve tical dis anc s from horizontal r fe enc

l ne() t o the p int at the t op an / r b tt om of the tan The e should be one p int in each segment

of the tank If p int at b th the t op an the b tt om of the tan ar measur d, the tit angle should be

calculat ed as an a e ag e of the slo es of fitt ed s raight lnes If p int at only one side of the tank (eithe

t op or b tt om) ar measur d, the tit angle should be calculat ed from the slo e of the fitt ed s raight lne

The same method should be used even if the diamet ers of the segment ar r g rded as (nearly)

identical in orde t o a oid any u ne es ary e rors

A levele ma be used t o det ermine the ti t of the tan b measuring the dife enc s in ve tical height

t o one or two chosen horizontal r fe enc l nes at a n mbe of sele t ed p int

R efe t o 1 2.2.3 for a detai ed desc iption of the method.

NOTE “t op” an “b tt om” refer t o the en s of the tan that are the highest an lowest positions on the tilted

tan On tan s with no tilt, either en could b “top” or “b tt om”

7.6 Plate thicknes

The plat e thick es shal eithe be measur d for each segment, w heneve p s ible, or taken from

the man factur r’ s drawings The plat e thick es for each segment shal be r corded t o the near s

0,5 mm P y sical measur ment ar pr fe r d t o r adings from drawings

Normal proc d r is t o measur two p int pe segment in any location Mode n ultrasonic ins rument

can dis inguish betwe n metal an p int If these ar not a aia le, the p int shal be sc a ed of prior

t o themeasur ment

NOTE The thick es of metal is req ired for pres ure cor ection; combined thick es (metal an paint) is

used t o calculate internal diameter from e ternal me surements

7.7 Referenc e height

Measur the o e al height at the r fe enc ga ug e hat ch If the e is a dip plat e (datum plat e), it height

a o e the b tt om of the tank should also be measur d in ac ordanc with ISO 7 0 -1

The dimensions an locations of the deadwo d shal be measur d, w heneve p s ible, or taken from

the drawings and theheight of the lowes an highes point of such deadwo d measur d in r lation t o

the datum p int of the tan The measur ment shal be r corded t o the near s 1 mm

7.9 Measurements of temperature and pres ur e

Tempe atur of the tank shel an pr s ur within the tan shal be used t o cor e t the calculat ed

v lume betwe n the calbration an r fe enc con itions

NOTE Similar cor ections are also done b tween the reference an operating con itions, but hese are not

the subjects of this document

Tempe atur r adings should be taken at a minimum of 1 wel-dis ribut ed p int arou d the tan shel

The t empe atur of the tan shel should be calculat ed asthe a e ag eof these multiple measur ment

If the tan is u de pr s ur w hen it is being calbrat ed, the pr s ur should be measur d using the

exis ing pr s ur g ug e

Cor e tions t o the v lume of horizontal cy lin rical tan sd e t o lq id head ma be ignor d as the efe t

is minimal d e t o the lmit ed dimensions, an henc hydros atic pr s ur s, of tan s of this ty e

Tanks shal be r -calbrat ed w heneve the cal bration be omes suspe t or the tan be omes phy sicaly

deformed

Ex mple F or e ample, d e t o movement of the tan fou dations, or as req ired by national re ulations

If new eq ipment afe ting deadwo d v lume is fitt ed or deadwo d is r mo ed, the tan calbration

ta le shal be r calculat ed If a bigg er o ening is r q ir d in the proc s , the tan shal be r calbrat ed

9 Desc ipti ve data

Desc iptive data should be ent er d on the tan calbration r cord It should contain tank desc iption

( in ependent of tan calbration) These would normaly inclu e sket ches, each complet ely identif ied,

dat ed an signed, that show the folowing:

a) tan n mbe an prod ct ID;

b) location, lengths an thick es es of segment from w hich the tank is as embled;

c) n mbe an siz of plat es pe segment ;

d) ty ical ve tical an cir umfe ential welding seams;

e) ar ang ement an siz s of noz les an manway s;

f) locations an siz s of dent an bulg es in shel plat es, if the e ar any

NOTE F rther details of the a ove can b fou d in ISO 75 7-1:2 0 ,An e D

Data r lat ed t o tank calbration that show s the folowing:

— dat e of calbration;

— identif ication of s an ard used for calbration (e.g ISO 1 9 7-1);

— method used in b p s ing (or cor e ting for) an o s ruction in the path of a cir umfe ential

— location of the ta e path if it is dife ent from that r q ir d b this documen

— a e ag e tank diamet er an cor espon ing v lume of ful tank ;

— lengths of the tan body an the tank en s;

— tit angle in degr es or radians;

— location (length from the lowes edg e of the tan b dy) of r fe enc (g ug e)poin

— measur d v lue of elev tion of dip plat e, if the e is any;

— measur d v lue of height of the r fe enc p int a o e the dip p int r fe enc height);

— prod ct level and density, pr s ur and shel t empe atur w hen the tank is cal brat ed;

— pr s ur an ambient t empe atur at r fe enc con itions (at w hich the cal bration ta le is

pr sent ed);

— ty e of g uge (in a e or ul a e) an it dir ction of measur ment (vertical or al gned with the

tank ends );

— t otal measura le level;

— detaied tan calbration ta le(v lume as function of ga ug ed level);

— signature /seal of the c rtifying authority

10 Computation oftank capacity table

10.1 General r ules

10.1.1 T e calculation methods g iven below la y down minimum r eq ir ements for pr ecision, but it is

pe mis ible to use alte nativepr oc d res, which pr od c a final tan ca acity table of simiar or g r eate

pr ecision A nnex A g ives a more complex (and more ac urate) method of calculating v lume Refe to

1 2 an A 1.2 for an aid in making a de ision a out which calculation method should be used

Unles othe wise spe if ied, volume shal be ex r s ed with an ac uracy of five signif icant digit

10.1.2 Tan ca acity tables pr ep r ed in ac or danc with the recommen ations set out below shal

bear the wor ds “ Calbr ated b the Ex te nal/Inte nal Manual Method in ac or danc with ISO 1 9 7-1.”

Nume ical r esolution should r elate to es imated u c rtainties Refer enc to GUMshould be added

10.1.3 T e stan ar d temperatur e an s an ar d pr es ure, for which the tan ca acity table has be n

calculated, shal ber ecor ded at the head of the table

10.1.4 A ll deadwo d shal be ac urately desc ibed g iving its v lume an location, in or de to pr ovide

adequate alowanc for the v lume of lq id displac d b the v rious items an to pr ovide for bes

estimates of the efe t at v rious elev tions within the tan

10.1.5 A ll measur ements shal be corrected for the mal ex pansion of the measuring devic s as s ated in

their r espe tive calbr ation she t

10.1.6 Tan calbration ta le shal also be corr ected for ex pansion of the tan shel at sele ted r eferenc

temperatur e an pr es ur e

10.2 Ac curacy ofvolume

10.2.1 General

Calculation of lq id v lume ma be based on a e ag e diamet er an t otal length of the tan body

Howeve , it should be bornein mind that e rors in measur d v lume would r sult if segment diamet ers

an / r segment lengths v ry

NOT Refer to A.1.2 for estimat e of er or resulting from using averag e diamet er an t otal length of tan b d

10.2.2 Calculatio parameter s

10.2.2.1 General

The v lume of the tank as fu ction of in ag e level (r lative t o the bott om of the tan , ignoring dip-plat e

( if the e is any) shal be calculat ed from the fol owing:

— a e ag e tank diamet er (from measur d cir umfe enc s of each in ivid al segment);

— tan tit, measur d from elev tions of each in ivid al segment

10.2.2.2 S g ment diameter

F or the ext ernal method, the diamet ers D

i

of in ivid al segment shal be calculat ed from measur d

cir umfe enc s C

ias:

Measur ment shal be pe formed as spe if ied a o e; multiple measur ment in each segment shal be

1 r efer ence line

W distances fr om the lowest point of the tan

X an Ypar ameter an varia les (se tex t)

γ angle of tilt w ith r eference line

Figure 4 — Angle of tit (o e reference lne)

1 top r eference line

2 b tom r efer ence line

X an Yparameter an varia les (se tex t)

W distances fr om the lowest point of the tan

γ ang le of tilt w ith r efer ence line

Figure 5 — Angle of ti t ( wo reference lnes)

R esulting eq ations ar as fol ow s

From measur d co rdinat es of al point , X

i

i, the slo e of f itt ed s raight l ne shal be calculat ed

using the normal formula for l near r gr s ion:

in

in

i

in

i

in

ar the co rdinat es of the p int in one l ne

Theangle of tit of thetan shal then be calculat ed for two r fe enc l nes as:

an for one r fe enc l ne as:

10.2.3 Volume calculatio

10.2.3.1 General

The sy st ematic calculations shal be buit up in thr e seq ential p rt :

a) calculation of the v lume of the cy lin rical p rt ofthe tank ( e 1 2.3.2);

b) calculation of the v lume of the tan en s ( e 1 2.3.3);

c) ad itional cor e tions shal then be made t o the v lume for deadwo d, working pr s ur an tank

shel tempe atur ( e 1 3 an 1 4)

10.2.3.2 Volume of cylndrical bod y

10.2.3.2.1 Me surements

This method calculat es v lume of the tank b dy at any angle of ti t The tank is as umed t o be a single

cy lin e with one diamet er

Measur d (an pr -calculat ed) p ramet ersand v ria les, asspe if ied in Figur 5:

D = a e ag e diamet er of the tan (m)

W = t otal length of the tan (m)

W

g

= dis anc of the g ug e from thelowes p int of the tank (m)

γ = angle of tit (rad)

Angle oftit γ = 0 ent er d in the folowing eq ations would r sult in z ro-divide-b -z ro If the tank has

no a p r nt tit, a non-z ro figur , e.g γ = 0,0 0 0 shal be ent er d int o the formulae

L

g

= ve tical elev tion (visgra ity)of the level g ug e a o ethe b tt om of the tank (m)

l = g ug ed (ve tical) in ag e level of the l q id (m)

h = g ug ed height (p ralel t o tank en s, de ived from g ug ed lq id level) (m)

10.2.3.2.2 Heights, levels and leng ths

Key

beliq id height at the lower edg e of empty tan

l me sur ed level (inclu es level of dip plate) W

ccylin er leng th

l

s

me sured level with liq id at the top of the lower edg eW

ggaug e leng th

h me sur ed heig ht inclu es heig ht of dip plate) W

g bgaug e leng th ofset d e to tan tilt

δH

g

nitleng th at the top of the tan cover ed by liq id

liq id heig ht at he lower edg e

Figure 6 — Heights and lengths in ti ted cy lindrical tanks

Al v ria les ar as spe ified in Figur 6

g

Calculat ed v ria le height :

height at lowe edg e:h

b

= h

be+ (l / cos γ + δH

g

NOTE 1 T e a ove me sured level,l, is, as shown, me sured t o the dip plate

NOTE 2 T e a ove calculat ed heights can b ne ative or gre ter than tan diameter

Calculat ed width at the t op of the tan co e ed b lq id in near-ful-tank s at e:

Figure 7 — Angle of co erag e

i/ 2)2

× W

c

(1 )

NOTE In e b in icates the b tt om an in e t the top of the tan

10.2.3.3 Volumes of tank ends

shal be those for extr me tank segment in A.3.2

These calculations shal be pe formed on non-tit ed tanks It is as umed that ti t makes only an

insignificant dife enc t o the v lumes of the tank en s Tit cor e tions ar not ne es ary for tank en s

NOTE Tan en s inclu e the straight cy lin rical) flang as shown in Figure 1

10.2.3.3.2 Tori sp er ical (knuckle-dish) ends

Calculation of the volume of the k uckle-dish en s shal be based on the folowing v ria les as spe if ied

in Figur 8:

a) radius of the k uckle, R

k(m);

b) radius of the dish, R

d

; or radius of the weld betwe n the dish an the k uckle R

2(m);

c) radius of the cy lin e , R = D / 2(m)

The measur d length of the head X

1shal be used eithe for calculation of the radius of the dish or for

che king the calculations

2

(radius of the weld betwe n kn ckle an dish) an X

1(head length) shal be measur d, then β shal

becalculat ed (n me icaly) from F rmula (1 ):

r adius of weld b twe n knuckle an dish

β angle of opening of the weld b tween knuckle an dish

difer ential elevation for calculation of β

X X-co r dinate of calculated cr os -sectional area

The v lume as a fu ction of lq id level ( h ) of the kn ckle dish shal then be calculat ed b the n me ical

int egration ac ording t o Simpson:

Figur s 9 an 1 show side view and a ial view, r spe tively, of the tank en for el ptical an sphe ical

en s These figur s should be r fe r d t o in 1 2.3.3.3.2and 1 2.3.3.3.3

x horizontal co r dinate of tan en cover ed w ith liq id

Figure 9 — Side view of semi el iptical and semispherical tank en s

10.2.3.3.3.2 S mi el iptical ends

The t otal v lume, V

t, shal becalculat ed from:

V

h

Rh