N e w M e x i i c o
W a t t e r r S y s s t t e m s s O p e r r a t t o r r
C e r r t t i i f f i i c c a t t i i o n S t t u d y G u i i d e
i

ii
N
M
W
S
O
C
S
G

This "WATER SYSTEMS OPERATOR CERTIFICATION STUDY GUIDE" has been created as a tool to assist Water Systems operators in New Mexico in preparation for taking the New Mexico
Distribution Systems Operator, Small Water Systems Operator, and Water Systems Operator certification exams. There are three classes of Distribution Systems Operator certification, two classes of Small Water Systems Operator certification, and four classes of Water System Operator certification. This guide is not intended to be a complete reference manual for technical information. Its purpose is to guide the reader to study material for each of the major subject areas for each of the classes. There is no implied claim that this study guide covers every possible point on which an operator may be tested. However, it is intended to be comprehensive in its coverage of the essential information for each exam.
This study guide is divided into thirteen chapters. Each chapter in the study guide has basic and advanced study questions and sample test questions that are intended help the individual determine the type of information that is covered in an exam. Basic questions will generally cover information in the Small Water Systems exams and the Class 1 and 2 for Water Systems and Distribution
Systems exams. Advanced questions will cover information in the Water Systems Class 3 and 4 and
Distribution Systems Class 3 exams. The study questions and sample test questions are designed to direct the reader to exam information that is related to the chapter topics. There is only one correct answer for the Sample Test Questions. No answer sheet is provided. You will have to look them up.
Distribution Systems exams will include information from Chapters I-IV, VI-IX and XII-XIII.
Small Water Systems exam will include information from Chapters I-IV, VI-X, and XII.
Advanced Small Water Systems exam will also include information from Chapters V and XI.
Water Systems Class 1 exam will include information from Chapters I-III, VI-X, and XII-XIII.
Water System Class 2 exam will include information from Chapters I-X and XII-XIII.
Water Systems Class 3 and 4 exams will include information from all thirteen chapters.
The certification exams use several texts as reference manuals for exam topics. Each chapter of the study guide contains references to specific chapters of these manuals for those who wish to access more information on the topics covered in that particular section.
Sacramento, Water Treatment Plant Operation , 4 th
Edition, 1999, Volumes 1-2
Sacramento, Small Water Systems O & M , 4 th
Edition, 2001
Sacramento, Water Distribution System O & M , 4 th
Edition, 2000
Fletcher Driscoll/US Filter , Groundwater and Wells , 2 nd
Edition, 1986
Special thanks to: NMED Facility Operations Section for funding, Bob Padilla for his graphics, Bill
Peifer for help with formatting and page munbers, the New Mexico Utility Operator Certification
Advisory Board for chapter reviews, and everyone that helped to proof read the first draft for typos.
F RED R AGSDALE , R AGSDALE AND A SSOCIATES
J ULY 5, 2002 iii

N EW M EXICO E NVIRONMENT D EPARTMENT
S URFACE W ATER Q UALITY B UREAU
F ACILITY O PERATIONS S ECTION
The New Mexico Water Quality Control Commission, through the New Mexico Environment
Department (NMED), grants certification for competency to the operators of water and wastewater systems. The Facility Operations Section (FOS) conducts the testing for certification. Certain requirements must be met before an operator is eligible to take a certification examination.
An operator begins the process by completing a test application from the Facility Operations
Section. Applications will only be accepted if they are submitted at least 30 days prior to the exam date. A certification officer will review each application to determine if the operator is eligible to take the requested examination. An application must be submitted every time a test is taken.
Examinations are given several times a year at various locations around the state. A fee of $15.00
for each examination must be paid to NMED Facility Operations Section . A check or money order for the proper amount must accompany each exam application.
Certificates must be renewed every three years. The renewal date will be the last day of the certificate holder's birthmonth following the third anniversary of the certificate. The FOS also handles renewal of certificates. The fee for renewal is $15.00
for each certificate.
The Facility Operations Section maintains training credits for certified operators only. Each operator must keep a record of all training credits earned. A record of current training credits is mailed to each certified operator yearly in July. Anyone who intends to apply for NM certification must include documentation of training credits when the application is submitted. Certified operators that are taking higher level exams may also have to submit training credit documentation to update training record files at the Facility Operations Section.
All correspondence, including applications, should be mailed to:
NMED Surface Water Quality Bureau
Facility Operations Section
PO Box 26110
Santa Fe, NM 87502
Please feel free to call the Facility Operations Section to request information on exam application forms, exam dates and locations, or certification and renewal. The telephone number for the office is 505-827-2804 . iv

An operator, as defined by NM Water Quality Control Commission Regulations, is "any person employed by the owner as the person responsible for the operation of all or any portion of a water supply system or wastewater facility. Not included in this definition are such persons as directors of public works, city engineers, city managers, or other officials or persons whose duties do not include actual operation or direct supervision of water supply systems or wastewater facilities."
Under the Utility Operator Certification Act, "a certified operator is a person who is certified by the commission as being qualified to supervise or operate one of the classifications of water supply systems or wastewater facilities". Experience is "actual work experience, full or part-time, in the fields of public water supply or public wastewater treatment. Work experience in a related field may be accepted at the discretion of the commission". Any claim of related experience will be reviewed by the WQCC or its advisory body, the Utility Operators Certification Advisory Board.
The Advisory Board is an appointed "seven-member board from the certified water systems operators and wastewater facility operators to function with the commission to establish qualifications of operators, classify systems, adopt regulations and advise the administration of the
Utility Operators Certification Act."
Experience that includes operation, maintenance or repair of water treatment and water distribution systems is accepted based on whether it is full or part-time. The Advisory Board will review and approve experience in other related fields, such as commercial plumbing or utility construction.
Credit for part-time experience will be based on the percentage of time devoted to actual operation or maintenance. Full time water or wastewater laboratory experience may be counted as operator experience at a rate of 25% of actual experience. The credit for this experience will be determined by review of the Advisory Board.
B ASIC C ERTIFICATION R EQUIREMENTS
There are three basic requirements an operator must meet to qualify for New Mexico certification.
All certified operators must have at least one year of actual experience in operation or maintenance of a public water system. All levels of certification require high school graduation or GED (see substitutions.) All levels of certification require a certain number of training credits in water systems O&M or related fields.
B ASIC C ERTIFICATION R EQUIREMENTS
Experience Training Credits
Class 1/ Small Systems 1 year* 10
Class 2
Class 3
2 years*
4 years*
30
50
Class 4
* - See Substitutions
1 year as Class 3 80
Education
HS Grad or GED*
HS Grad or GED*
HS Grad or GED*
HS Grad or GED v

S UBSTITUTIONS
One year of additional experience may be substituted for the high school graduation or GED requirement for all classes except Class 4. Education may be substituted for experience or training credits in some cases. The education must be in a water or wastewater related field. One year of vocational education can be substituted for up to one year of experience. Associate's and Bachelor's degrees in a related field may be substituted for up to three years of experience and 50 training credit hours, depending on the amount of actual experience. The criteria for substitution of education for experience are as follows:
No more than one year (30 semester hours) of successfully completed college education in a non-related field may be substituted for an additional six months of the required experience.
One year of approved vocational school in the water and/or wastewater field may be substituted for only one additional year of the required experience.
An associate's degree for a two-year program in an approved school in the water and/or wastewater field and six months of actual experience in that field (which may be accrued before, during, or after the school program) may be substituted for the requirements of any level up to and including Class 2 . An associate's degree for a two-year program in an approved school in the water and/or wastewater field and twelve months of actual experience in that field
(which may be accrued before, during, or after the school program) may be substituted for the requirements of any level up to and including Class 3 .
Completion of at least three year s of actual experience in the water and/or wastewater field plus high school graduation or equivalent, plus 15 semester hours of successfully completed college education directly related to the water or wastewater field may be substituted for any level up to and including Class 3 .
A bachelor's degree for a major directly related to the water or wastewater field plus two years of actual experience in that field may be substituted for any level up to and including Class 3 . vi

C HAPTER I: I NTRODUCTION T O W ATER S YSTEMS
M
EETING
W
ATER
S
YSTEM
D
EMANDS
D OMESTIC W ATER U SAGE
I NDUSTRIAL W ATER U SAGE
A
GRICULTURAL
W
ATER
U
SAGE
P
UBLIC
W
ATER
U
SAGE
S OURCES OF S UPPLY
M
EETING
W
ATER
Q
UALITY
S
TANDARDS
M
EETING
W
ATER
C
ONSUMPTION AND
P
EAK
D
EMANDS
S EASONAL D EMANDS
D
AILY
P
EAK
D
EMANDS
C
OMPONENTS OF
A W
ATER
S
YSTEM
W ATER S OURCES AND T REATMENT
D ISTRIBUTION AND T RANSMISSION
–W
ATER M AINS
S
ERVICES
P
UMPS
S TORAGE T ANKS
C
ONTROLS
I
SOLATION
V
ALVES
C ONTROL V ALVES
S URGE T ANKS
F
IRE
H
YDRANTS
O PERATORS R ESPONSIBILITY
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
I-4
I-4
I-4
I-4
I-4
I-5
I-5
I-5
I-1
I-1
I-1
I-1
I-2
I-2
I-2
I-2
I-2
I-3
I-3
I-3
I-3
I-3
I-3
C HAPTER II: S AFE D RINKING W ATER A CT
P
UBLIC
W
ATER
S
YSTEMS
P
RIMARY
C
ONTAMINANTS
M AXIMUM C ONTAMINANT L EVELS (MCL)
I NORGANIC C ONTAMINANTS
L
EAD AND
C
OPPER
R
ULE
N ITRATES
F LUORIDE
T
URBIDITY
O
RGANIC
C
ONTAMINANTS
R ADIOACTIVE C ONTAMINANTS
B
ACTERIOLOGICAL
C
ONTAMINANTS
S
ECONDARY
C
ONTAMINANTS
M ONITORING AND R EPORTING
S AMPLING S CHEDULE
II-1
II-1
II-2
II-2
II-2
II-3
II-3
II-3
II-3
II-4
II-4
II-4
II-5
II-5 vii

C HAPTER II: S AFE D RINKING W ATER A CT ( CONT .)
B
ACTERIOLOGICAL
V
IOLATIONS
P
UBLIC
N
OTIFICATION
A CTION P LANS FOR V IOLATIONS
V
ARIANCES AND
E
XEMPTIONS
S
URFACE
W
ATER
R
ULE
D ISINFECTION
–D
ISINFECTION B Y -P RODUCTS R ULE
S
TUDY
Q
UESTIONS AND
S
AMPLE
T
EST
Q
UESTIONS
C HAPTER III: W ATER S AMPLING
N
EW
M
EXICO
W
ATER
C
ONSERVATION
F
EE
W ATERBORNE P ATHOGENS
C
OLIFORM
G
ROUP OF
B
ACTERIA
S
AMPLING
S
CHEDULES AND
T
ECHNIQUES
S AMPLING S CHEDULES
S
AMPLING
T
ECHNIQUES
R
EPORTING AND
S
HIPPING
C
ONSIDERATIONS
R ETAKES AND V IOLATIONS
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER IV: D ISINFECTION
C
HLORINE
G
AS
C
HLORINE
P
OWDER
C HLORINE B LEACH
C
HLORINE
T
REATMENT
T
ERMS
C
HLORINE
D
OSAGE
C HLORINE D EMAND
C
HLORINE
R
ESIDUAL
F
REE
C
HLORINE
R
ESIDUAL
C OMBINED C HLORINE R ESIDUAL
D ISINFECTION R EQUIREMENTS
E
FFECTS OF
T
EMPERATURE AND
PH
B
REAKPOINT
C
HLORINATION
T ESTING FOR C HLORINE R ESIDUALS
G
ENERAL
C
HLORINE
S
AFETY
C
HLORINATOR
R
OOM
C HLORINE S TORAGE
C HLORINE C YLINDERS
HTH H
ANDLING
S
AFETY
R
ESPIRATORY
P
ROTECTION
G AS M ASKS viii
II-6
II-6
II-6
II-6
II-7
II-7
II-7
IV-1
IV-1
IV-1
IV-2
IV-2
IV-2
IV-2
IV-3
IV-3
IV-3
IV-3
IV-4
IV-5
IV-6
IV-6
IV-7
IV-7
IV-8
IV-8
IV-8
III-1
III-1
III-2
III-2
III-2
III-2
III-3
III-4
III-4

C HAPTER IV: D ISINFECTION ( CONT .)
S
ELF
-C
ONTAINED
B
REATHING
A
PPARATUS
(SCBA)
C
HLORINATION
E
QUIPMENT
G AS C HLORINATION
H
YPOCHLORINATION
S
YSTEMS
E
MERGENCY
R
ESPONSE
P
ROCEDURES
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER V: F LUORIDATION
F
LUORIDE
F
EED
S
YSTEMS
S
ODIUM FLUORIDE
S
ATURATORS
M ONITORING F LUORIDE C ONCENTRATIONS
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER VI: D ISTRIBUTION S YSTEMS
P
IPES
C AST I RON AND D UCTILE I RON P IPE
S
TEEL
P
IPE
A
SBESTOS
-C
EMENT
P
IPE
P OLYVINYL C HLORIDE P IPE
S
PECIAL
C
ONSIDERATIONS FOR
L
AYING
PVC P
IPE
B
ACKFILL
C
ONSIDERATIONS
P IPE P RESSURE R ATINGS
S EPARATIONS OF W ATER AND S EWER L INES
C
LEANING
W
ATER
L
INES
W
ATER
L
INE
R
EPAIRS
L OCATING L EAKS
R
EPAIRING THE
L
EAK
D
ISINFECTION OF
W
ATER
L
INES
D ISTRIBUTION S YSTEM V ALVES
G
ENERAL
V
ALVE
M
AINTENANCE
G
ATE
V
ALVES
B UTTERFLY V ALVES
B ALL OR P LUG V ALVES
C
HECK
V
ALVES
A
IR
R
ELEASE
V
ALVES
C ONTROL V ALVES
A
LTITUDE
V
ALVES
P
RESSURE
R
EDUCING
V
ALVES
P RESSURE R ELIEF V ALVES
P
RESSURE SUSTAINING
V
ALVES
F
IRE
H
YDRANTS
S ERVICES
W ATER M ETERS
IV-8
IV-9
IV-9
IV-12
IV-13
IV-14
V-1
V-2
V-2
V-3
VI-4
VI-4
VI-5
VI-5
VI-6
VI-7
VI-8
VI-8
VI-8
VI-9
VI-1
VI-1
VI-1
VI-2
VI-2
VI-2
VI-3
VI-4
VI-10
VI-10
VI-10
VI-10
VI-10
VI-11
VI-11
VI-11
VI-12
VI-13
VI-13 ix

C HAPTER VI: D ISTRIBUTION S YSTEMS ( CONT .)
P
OSITIVE
D
ISPLACEMENT
M
ETERS
T
URBINE
/C
URRENT
M
ETERS
V ENTURI M ETERS
R
EADING
M
ETERS
D
ISTRIBUTION
S
YSTEM
H
YDRAULICS
F RICTION L OSS
W
ATER
H
AMMER
T
HRUST AT
P
IPE
B
ENDS
C ORROSION C ONTROL
C ORROSIVE W ATER /C HEMICAL S TABILITY
B
AYLIS
C
URVE
G
ALVANIC
C
ORROSION
E LECTROLSYSIS
C
ORROSIVE
S
OIL
C
ROSS CONNECTIONS
B ACKFLOW AND B ACK S IPHONAGE
A IR G AP
V
ACUUM
B
REAKERS
R
EDUCED
P
RESSURE
Z
ONE
B
ACKFLOW
P
REVENTION
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER VII: W ATER S TORAGE
G ROUND S TORAGE T ANKS
C
ONSTRUCTION OF
G
ROUND
S
TORAGE
T
ANKS
D
ESIGN
C
APABILITIES OF
G
ROUND
S
TORAGE
T
ANKS
L OCATION OF G ROUND S TORAGE T ANKS
P
ROTECTION OF
G
ROUND
S
TORAGE
T
ANKS
F
IRE
P
ROTECTION
C ATHODIC P ROTECTION
L
EVEL
I
NDICATORS
E
LECTRODE
S
YSTEMS
F LOAT S YSTEMS
P RESSURE S ENSING S YSTEMS
H
YDROPNEUMATIC
S
TORAGE
T
YPES OF
P
NEUMATIC
T
ANKS
S IZING A P NEUMATIC S YSTEM
S
TUDY
Q
UESTIONS AND
S
AMPLE
T
EST
Q
UESTIONS
C HAPTER VIII: P UMPS AND M OTORS
C ENTRIFUGAL P UMPS
T
YPES OF
C
ENTRIFUGAL
P
UMPS
C ENTRIFUGAL P UMP C OMPONENTS
P UMP H YDRAULICS x
VI-14
VI-15
VI-15
VI-15
VI-16
VI-16
VI-17
VI-17
VI-18
VI-18
VI-18
VI-19
VI-19
VI-19
VI-19
VI-19
VI-20
VI-20
VI-21
VI-22
VII-1
VII-1
VII-1
VII-1
VII-2
VII-2
VII-2
VII-3
VII-3
VII-3
VII-3
VII-4
VII-4
VII-5
VII-6
VIII-1
VIII-3
VIII-6
VIII-12

C HAPTER VIII: P UMPS AND M OTORS
P UMP C HARACTERISTIC C URVES
S
HUTOFF
H
EAD
C
HECKING
S
HUTOFF
H
EAD
C OMMON O PERATIONAL P ROBLEMS
C AVITATION
A
IR
L
OCKING
L OSS OF P RIME
E LECTRIC M OTORS
P
HASES
S
INGLE
P
HASE
M
OTORS
T HREE P HASE M OTORS
S
INGLE
P
HASING
C
IRCUIT
P
ROTECTION
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER IX: M ECHANICAL S YSTEMS O & M
P
UMP
M
AINTENANCE
P
UMP
P
ACKING
R EMOVING O LD P ACKING
R
EPACKING THE
P
UMP
A
DJUSTING THE
P
ACKING
G
LAND
B EARING M AINTENANCE
C OUPLINGS
A
LIGNMENT
I
NSTRUMENTATION
C HEMICAL F EED S YSTEMS
S
TUDY AND
S
AMPLE
T
EST
Q
UESTIONS
C
HAPTER
X: G
ROUNDWATER AND
W
ELLS
H
YDROLOGIC
C
YCLE
G
ROUND
W
ATER
S
UPPLIES
W ATER T ABLE A QUIFER
A RTESIAN W ELLS
T
YPES OF
G
ROUND
W
ATER
F
ORMATIONS
W
ATER
W
ELL
L
OCATION
S ANITARY C ONSIDERATIONS
W
ATER
W
ELL
C
ONSTRUCTION
C
ABLE
T
OOL
M
ETHOD
R OTARY D RILLED W ELLS
V ERTICAL C ASEMENT A LIGNMENT
S
ANITARY
P
ROTECTION OF THE
W
ELL
X-1
X-2
X-2
X-2
X-2
X-2
X-4
X-4
X-4
X-4
X-4
X-5
IX-1
IX-1
IX-2
IX-2
IX-3
IX-5
IX-5
IX-6
IX-7
IX-8
IX-11
VIII-14
VIII-15
VIII-15
VIII-16
VIII-16
VIII-17
VIII-17
VIII-18
VIII-18
VIII-18
VIII-18
VIII-19
VIII-19
VIII-20 xi

C HAPTER X: G ROUNDWATER AND W ELLS
D EVELOPING A W ELL
G
RAVEL
P
ACKED
W
ELLS
D
ISINFECTING
A W
ELL
W ELL P UMPS
V ERTICAL T URBINE I NSTALLATIONS
L
INE
S
HAFT
P
UMPS
L INE S HAFT B EARINGS
O IL D RIPPER S YSTEMS
A
DJUSTING
D
RIPPER
S
YSTEMS
W
ELL
S
CREENS
W ELL H YDRAULICS
M
EASURING
S
TATIC AND
P
UMPING
L
EVELS
T
HE
W
ELL
L
OG
T ROUBLESHOOTING W ELL P ROBLEMS
W ELL R ELATED P ROBLEMS
C
LOGGED
W
ELL
S
CREENS
S
AND
B
RIDGING
I RON B ACTERIA
L
IME
S
CALING
C
LEANING
I
NCRUSTED
W
ELL
S
CREENS
P UMP R ELATED P ROBLEMS
A
DJUSTING
I
MPELLER
C
LEARANCE
S
TUDY
Q
UESTIONS AND
S
AMPLE
T
EST
Q
UESTIONS
C HAPTER XI: S URFACE W ATER
L
AKES AND
R
IVERS
I NTAKE S TRUCTURES
R
IVER AND
S
TREAM
I
NTAKES
L
AKE AND
R
ESERVOIR
I
NTAKES
S URFACE W ATER Q UALITY
M
INERALS
T
URBIDITY
B ACTERIA
T ASTE AND O DOR
C
OLOR
S
OLUBILITY OF
S
ALTS
C OMMON N AMES FOR W ATER T REATMENT C HEMICALS
P
H
P
HYSICAL
/C
HEMICAL
T
REATMENT
R EMOVAL OF C OLOR
R EMOVAL OF B ACTERIA
R
EMOVAL OF
T
ASTE AND
O
DOR
C
OPPER
S
ULFATE
T
REATMENT
I N -P LANT T REATMENT
R
EMOVAL OF
T
URBIDITY
R
EMOVAL OF
M
INERALS xii
X-17
X-17
X-18
X-18
X-18
X-19
X-20
X-20
X-23
X-6
X-7
X-8
X-8
X-8
X-10
X-10
X-10
X-12
X-12
X-13
X-14
X-16
X-17
XI-6
XI-6
XI-7
XI-8
XI-9
XI-9
XI-9
XI-10
XI-10
XI-11
XI-1
XI-2
XI-2
XI-2
XI-3
XI-3
XI-4
XI-4
XI-4
XI-4
XI-5

C HAPTER XI: S URFACE W ATER
H
ARDNESS
S
OFTENING
C
HEMICAL
R
EACTIONS
R ECARBONATION
O
THER
S
OFTENING
P
ROCESSES
I
RON AND
M
ANGANESE
D ISSOLVED G ASES
O
THER
M
INERAL
P
ROBLEMS
C
HEMICAL
F
EEDERS
P RETREATMENT E QUIPMENT
C OAGULATION E QUIPMENT
F
LOCCULATION
E
QUIPMENT
S
EDIMENTATION
E
QUIPMENT
U P -F LOW C LARIFIERS
F
ILTRATION
E
QUIPMENT
P
RESSURE
F
ILTERS
S LOW S AND F ILTERS
R APID S AND F ILTERS
F
ILTER
O
PERATION
B
ACKWASHING
F
ILTERS
F ILTER B ACKWASHING P ROCEDURES
T
ROUBLESHOOTING
F
ILTER
P
ROBLEMS
C
LEANING
F
ILTER
B
EDS
H IGH R ATE F ILTERS
S
TUDY
Q
UESTIONS AND
S
AMPLE
T
EST
Q
UESTIONS
C HAPTER XII: S AFETY
L OCK O UT /T AG O UT (LOTO)
C
ONFINED
E
NERGY
S
PACE
H
AZARD
C
OMMUNICATION
NFPA C OLOR C ODE W ARNING S YSTEM
E
XCAVATION
S
AFETY
S TUDY Q UESTIONS AND S AMPLE T EST Q UESTIONS
C HAPTER XIII: M ATHEMATICS FOR W ATER O PERATORS
P
RESSURE
F
LOW
A REAS
V OLUMES
XI-12
XI-12
XI-13
XI-14
XI-15
XI-16
XI-16
XI-16
XI-17
XI-17
XI-19
XI-20
XI-22
XI-24
XI-24
XI-25
XI-25
XI-29
XI-29
XI-30
XI-31
XI-31
XI-31
XI-33
XII-1
XII-2
XII-2
XII-4
XII-5
XII-5
XIII-1
XIII-2
XIII-3
XIII-3 xiii

C HAPTER XIII: M ATHEMATICS FOR W ATER O PERATORS
V
OLUMES IN
G
ALLONS
V
OLUMES OF
P
IPES
V ELOCITY
D
ETENTION
T
IME
D
OSAGE
W IRE TO -W ATER C ALCULATIONS
S
AMPLE
T
EST
Q
UESTIONS
XIII-4
XIII-4
XIII-5
XIII-6
XIII-7
XIII-10
XIII-13 xiv