Chapter 6 Power Point

Chapter 6
INSTRUMENTS USED FOR PIPING
SYSTEMS LAYOUT

Instruments for Pipe Layout
 The ability to use a transit, builders level, pipe
laser or other instrument is very important in the
layout and installation of piping systems. When
installing underground piping systems, it is
necessary to know where and how deep they
must be installed. For most installations, invert
elevations and location of utilities will be shown on
the drawings. On many jobs, the actual laying-out
of the location and depth of underground piping
systems becomes the work of the pipe trades
journeyworker.

 When a piping installation plan does not
give the elevation of underground utilities,
the journeyworker may he responsible for
establishing the invert elevations and
coordination of piping systems by means
of a profile drawing.

 In some cases, utility contractors will do the
installation of public sewer and water mains.
However; the ultimate responsibility for the grades
and location of on- site underground utilities and
piping systems belongs to the pipe trades
journeyworker. In this case, knowing how to use a
transit, level or other instrument of similar
capabilities, will enable the journeyworker to
ensure the particular utility system will be installed
as designed.

 This chapter deals with the practical use
of instruments commonly used by
surveyors and construction
superintendents. In piping installations,
these instruments are used by
journeyworkers. Work carefully; check
your work for accuracy; and check again.

 The Job Safety and Health Training
Manual, published under the direction of
the United Association Training
Department, contains information
concerning the correct and safe methods
for performing excavation and trenching
operations in accordance with OSHA
Regulations.

 1. It’s getting crowded underground.
Virtually anywhere you need to dig, there
are probably underground facilities
somewhere in the vicinity. The occasional
gas and water pipes are being joined by
growing networks of telephone cable,
power lines and cable TV leads. The odds
of an excavator moving something besides
dirt are getting stronger all the time.

 Even if you see overhead lines, that doesn’t rule
out the existence of buried electric power, cable
television or telephone facilities. Many utility
companies have long-term programs to
weatherproof their systems by putting them
underground. Both aerial and underground
facilities may be in use during transitions. Even
water-filled ditches and streams may have
underground utilities. A ditch may have been dry
when utilities were buried. A stream may have
been diverted.

 Even “open country” may conceal buried utilities.
Large pipelines and cables are especially
expensive to place, so utilities often cut across
country to reduce total yardage for major
installations. You can be positive that buried
utilities are located in virtually all road right of
ways. They can be found almost always along lot
lines and between lot lines and any building
located on a lot. Damage to buried utilities most
often occurs when excavators do not call for utility
locations before they

 dig. This isn’t the only factor however. In
many cases, utilities are damaged even
after calls have been made and locations
clearly marked. That’s usually because
many excavators do not know the
procedures for safely excavating around
the buried facilities. Damage also results
from improper backfilling around exposed
utilities.

 In many states it is against the law to
perform any type of excavation work prior
to notifying proper authorities such as
Miss Utility. What are twelve questions
which are usually asked by authorities
concerning the type(s) of information
needed prior to them going to a job site to
give approval to excavate a ditch or
trench?

 Twelve questions are;
 1. Caller Name and Company Name. The
caller’s name and the company name are
taken in order to maintain records of all
locate requests. This information is also
helpful in the event it is necessary to
contact someone for further information.

 2. Mailing Address. The mailing address of
the caller or the caller’s company is
recorded in order to enable [lie computer
to store this information in a mailing list
database. This mailing list maybe utilized
to notify excavators of information
pertaining to Miss Utility on a periodic
basis.

 3. Telephone Number. The telephone number
(with area code) of the caller is taken in case
additional information is required at a later date
and for use by those underground facility
operators who call to respond to an emergency
excavation request or to change a meeting
request. The phone number is also used as a key
to activate computer databases which can fill in
the answers for Questions 1 through 4.

 4. Call Back Number. If the person in
charge of the work is at a different
telephone number than the caller, an
alternate number is needed. Locate
requests can often he expedited when the
person supervising the work can be
reached directly.

 5. Location. To ensure that all
underground facility operators can find the
location of the locate request, Miss Utility
has requirements for identifying the
location of the job site. The best
information is a street address. If a street
address is not available, the answering
attendant will ask for the following
information;

 A. Name of street or route number
 B. Name of nearest intersecting street or route
 C. Name of subdivision (if any) or area name
 The following is an example of proper information
when identifying the location of a job site;
 313 Washington Court off Washington Street in
Beechwood Estates Subdivision

 6. Instructions. After identifying the
location of the job site, answering
attendants will identify what portion of the
job site is to be marked. In identifying this
area, the following guidelines should be
considered:
 A. Right and left should not be used as
directions since they are relative points of
view.

 B. If the excavation is in a roadway, marking
instructions could include:
 i. Mark from curb to curb
 ii. Mark from lot llne to lot line in the road right of
way
 iii. Mark from the center line of road to North,
South, East, West lot line or curb
 C. In all cases, Miss Utility is looldng for a
description of the area to be marked.

 7. Work Type. Field locators need to know
the specific reason for excavation.
Therefore, answering attendants need to
know the reason for the work. For
example, “installation of a sanitary sewer
lateral” is much more helpful than digging
for sewer line,

 8. Work Date and Time. It is very
important not to begin work prior to the
legal start date and time. Beginning work
before the legal start date and time can
result in forfeiture of the excavator’s rights
and protection.

 9. Done for. The identification of who the
work is being performed for is another
resource for obtaining additional
information about the project. The
customer’s name or the general
contractor’s name is sufficient.

 10. City or County. The name of the city or
county in which the work will be
performed is needed to identify where the
job site is located.

 11.. Grid. The answering attendant will
ask the caller for the map page and grid
where the job site is located. This
information is used to determine which
underground facility operators will be
notified.

 12. Remarks. Miss Utility answering
attendants will also record any information
deemed appropriate regarding driving
instructions, etc., to get the locator to the
job site.

 2. What happens after the call is made?
 After the answering attendant completes the
locate request, the ticket is processed by the
computer at Miss Utility. The computer analyzes
the grid on the ticket to identify which
underground facility operators have elected to
receive the information. The computer transmits
the message to the underground facility operators
via direct dial communication links. Underground
facility operators receive the information on
terminal equipment.

 This information is received at the operator’s
mapping or screening departments. Trained
personnel review the locate request in comparison
with their maps and records. It is their job to
decide whether or not the location of the work site
is close to existing underground facilities.
Underground facility operators should call back a
confirmation of the locate request indicating that
the work site is either clear of that operators’
facilities or that a potential conflict exists and the
operator will mark, or has marked, the facilities as
requested.

 Once it is determined that markings are
required, the ticket is dispatched to a field
locator who will locate and mark the
excavation site with paint, stakes, and/or
flags. Operators mark facilities according
to specific guidelines and color codes.

 3. What are the responsibilities of the facility
operator after receiving the locate request?
 After receiving and screening the locate request,
the underground facility operator will mark, in a
reasonable manner, the location of facilities in the
field in order to enable the excavator to easily
recognize the location of buried facilities.
Underground facility operators will usually mark
facilities according to the following color codes in
accordance with State Code.

 RED — Electric Power Lines, Cables,
Conduit and Lighting Cables
 YELLOW — Gas, Oil, Steam, Petroleum or
Gaseous Materials
 ORANGE — Communication, Cable TV,
Alarm or Signal Lines, Cables or Conduit
 BLUE — Water, Irrigation or Slurry Lines
GREEN — Sewer and Drain Lines

 Underground facility operators will use
either stakes, flags, paint, or other
suitable materials in varying combinations
dependent upon the type of surface to be
marked. These marks will be in sufficient
quantity to clearly identify the routes of
the facility. The markings should also
include the symbols of the underground
facility owner.

 When the surface over the underground
facility is expected to he destroyed,
supplemental offset marking may be
added. Such markings will identify the
direction and distance to the actual facility.
Supplemental markings may he added at
the discretion of the facility owner.

 Emergency locations are given top priority.
Underground facility operators will mark facilities
within the emergency excavation area as soon as
practical, generally within three hours or prior to
the start of the excavation.
 If requested, underground facility operators will
attempt to expedite non-emergency locate
requests depending upon scheduling
considerations. Every effort will be made to
comply with early start date requests.

 Underground facility operators will, upon
receiving a request through Miss Utility,
usually re-mark a job site. If the re-
marking request is received within 48
hours of the original start date, operators
will re-mark facilities, generally within 48
hours.

 4. What responsibilities are usually required of the
excavator?
 Many people believe that by notifying Miss Utility
of intended excavation, they have completed all of
their responsibilities with respect to the locating
process. This is not the case. Notifying Miss Utility
is only the first step and there are several other
responsibilities which need to be considered.

 After the markings have been made, excavators
are required to maintain a minimum clearance of
two feet between a marked and unexposed
transmission facility and the cutting edge or point
of any power-operated excavating or earth-moving
equipment. If excavation is required within two
feet of any marking, the excavation should be
performed very carefully with hand tools.

 If, during the course of excavation, a facility has
been exposed, it is the excavator’s responsibility to
inspect and support the facility or facilities if more
than one, prior to backfilling in order to ascertain
if the facilities have been struck or damaged. If
damage of any kind is discovered or any suspicion
of damage exists, it is the excavator’s
responsibility to immediately notify the facility
owner directly.

 Many excavators mistakenly believe that Miss
Utility is responsible for the actual marking of
facilities. This is not the case. Miss Utility takes
information from the excavator and relays it to the
underground facility operators. Each facility
operator is responsible for ensuring that their
facilities are properly marked. When one
underground facility operator indicates there are
no facilities in conflict with a specific excavation,

 the excavator must realize this does not mean that
Miss Utility has cleared the site; nor does it mean
that other facilities are not at that location.
Excavators are reminded not to begin excavation
until all underground facilities have been marked,
including those that might be operated by facility
operators not having membership with Miss Utility
and, therefore, not notified of the excavation by
Miss Utility.

 Note: All private lines should be identified
by the facility owner before excavation.
 5. Laying out pipe work for underground
piping systems must be done correctly.
One of the most accurate methods of
layout for excavation work is done with
the use of a combination transit and level.
What are the features of this instrument?

 The level element of this instrument is
basically the same as a surveyors level.
The transit part is less refined than a
surveyors transit, but can be used to a
degree of accuracy sufficient for layout,
excavation and installation of underground
piping systems. The combination transit
and level combines the surveyors transit
and a level in one instrument.

 6. When laying out an excavation for a piping
system, the depth of the piping system below the
ground surface must be determined. In order to
find that depth, it is first necessary to record
accurately the elevation of the ground surface.
How is this accomplished?
 The surface of the ground can be accurately
recorded by measuring from a level plane,
projected from a known elevation.

 7. What means can be used to project a
level plane?
 A level plane can be projected by sighting
through the telescope of the instrument
after it has been set up in a level position,
as illustrated in Fig. 6-1.

 8. How is the elevation of the ground
surface recorded from a projected level
plane?
 Ground surface elevation is recorded by
sighting along the level plane and taking a
series of measurements from the
projected level plane to the ground, as
illustrated in Fig. 6-2.

 9. Finding the depth of excavation is only one
important step in the layout of an underground
piping system. The location and direction of the
piping must also be established. What part of a
combination transit and level is used in laying out
the location and direction of an underground
piping system?
 Location and direction are laid out by using the
transit part of the instrument.

 10. What makes the instrument
(combination transit and level) similar to a
surveyors transit?
 The combination transit and level contains
a horizontal protractor which is used for
laying out horizontal angles and a vertical
protractor for laying out vertical angles.
See Fig. 6-3-A and B.

 The 360° horizontal circle on the
protractors is divided in quadrants (0-90°).
The circle is marked by degrees and
numbered every 10 degrees. See Fig. 6-3-
C.

 To obtain degree readings it is only
necessary to read the exact degree at the
intersection of the zero index mark on the
vernier and the degree mark on the circle
(or on the vertical arc of the level transit).

 For more precise readings, the vernier scale is
used. See Fig. 6-3-D. The vernier lets you
subdivide each whole degree on the circle into
fractions, or minutes. There are 60 minutes in a
degree. If the vernier zero does not coincide
exactly with a degree mark on the circle, note the
last degree mark passed and, reading up the
vernier scale, locate a vernier mark that coincides
with a circle mark. This will indicate your reading
in degrees and minutes.

 11. The horizontal circle of a combination transit
and level is usually graduated into degrees and
half-degrees or 30 minutes. See Fig. 6-4. It is not
unusual to find the horizontal circle graduated into
degrees and one-third degrees (20 minutes). To
determine an angle value more accurately than
the least count of the circle (30 or 20 minutes),
vernier scales are employed. Fig. 6-5 shows a
double vernier scale

 alongside a transit circle. The left vernier scale is
used for clockwise circle readings (angles turned
to the right) and the right vernier scale is used for
counterclockwise circle readings (angles turned to
the left). What determines which vernier (left or
right) scale is to be used?
 The vernier scale to be used is the one whose
graduations are increasing in the same direction
as are the circle graduations.

 12. The vernier scale is constructed so that 30
vernier divisions cover the same length of arc as
do 29 divisions (half degrees) on the circle. The
width of one vernier division is (29/30) x 30’ = 29’
on the circle. Therefore, the space difference
between one division on the circle and one
division on the vernier represents 01’. The first
division on the vernier shown in Fig. 6-5 (left or
right of the index mark) fails to exactly line up
with the first division on the circle (left or right) by
01’. The second division on the

 vernier fails to line up with the corresponding
circle division by 02’, and so on. If the vernier
were moved so that its first division exactly lined
up with the first circle division (30’ mark), the
reading would be 01’. If the vernier again were
moved the same distance at arc (1’), the second
vernier mark would now line up with the
appropriate circle division line, indicating a vernier
reading of 02’. How is the vernier read?

 The vernier is read by finding which
vernier division line exactly coincides with
any circle line, and by then adding the
value of that vernier line to the value of
the angle obtained from reading the circle
to the closest 30’. See Fig. 6-5.

 13. In Fig. 6-6-A the circle is divided into degrees
and half-degrees (30’). Before even looking at the
vernier, you know that its range will be 30’ (left or
right) to cover the least count of the circle.
Inspection of the vernier shows that 30 marks
cover the range of 30’, indicating that the value of
each mark is 01’. (Had each of the minute marks
been further subdivided into two or three
intervals, the angle could then have been read to
the closest 30” or 20”.) Explain.

 If you consider the clockwise circle readings (field
angle turned left to right), you will see that the
zero mark is between 184° and 184°30’; the circle
reading is therefore 184°. To find the value to the
closest minute use the left side vernier and,
moving from the zero mark, look for the vernier
line which exactly lines up with a circle line. In this
case, the 08’ mark lines up; this is confirmed by
noting that both the 07’ and 09’ marks do not line
up with their corresponding circle mark, both by
the same amount. The angle for this illustration is
184° + 08’ = 184°08’.

 If you consider the counterclockwise circle
reading in Fig. 6-6-A, you will find that the
zero mark is between 175°30’ and 176°;
the circle reading is 175°30’, and to that
value add the right side vernier reading of
22’ to give an angle of l75°52’. As a check,
the sum of the clockwise and
counterclockwise readings should be
360°00’.

 14. All transits are equipped with two double
verniers located 1800 apart. Although theoretically
increased precision can be obtained by reading
both verniers for each angle, usually only one
vernier is employed. As mentioned earlier, the
double vernier permits angles to be turned to the
right (left vernier) or to the left (right vernier).
What direction are field angles usually turned?

 Field angles are usually turned only to the right.
 Note: A few minutes spent studying the circle and
vernier graduations shown in Fig. 6-6-B and C will
disclose the proper technique required for reading.
 The use of a magnifying glass (5 x) could be
helpful in reading the scales, particularly for the
30 and 20’ verniers.

 15. The most used, practical application of
a combination transit and level
(instrument) in the pipe trades is in the
laying-out of a ditch or trench to
accommodate underground pipe. What is
the first step in laying out a ditch?

 A ditch or trench is laid out by first
determining from the plans the location
where the underground pipe is to be
installed and then using the instrument to
locate the straight portions between each
change of direction on the job site.

 16. What is the procedure for determining the
depth of a pipeline after the location and direction
have been established?
 The depth of a pipeline is determined by using the
instrument as a level and recording the elevation
of the ground surface at several points along the
line. Then, to establish depth, the actual elevation
of the pipeline is compared to the ground
elevations.

 17. Established elevations within a building
or job site also play an important role in
the installation of a piping system. When
should an instrument be used within a
building or on a job site?
 An instrument should be used when drains
or equipment must be installed accurately
to a known or given elevation.

 18. Although a combination transit and level is less
sensitive than a surveyors transit, it still requires
careful handling. When using a combination transit
and level, an established pattern should be
followed in setting up the instrument and in
recording elevations. What is the first step
preliminary to using an instrument?
 It is first, necessary to become familiar with the
working components of the instrument.

 19. Fig. 6-7 is an illustration of a a
combination transit and level. Instruments
of this type differ in construction, but their
basic components are the same. Study
Fig. 6-7 and then, on a piece of paper,
write the names of the parts shown.

 20. Levels similar to the one shown in Fig.
6-8 are sometimes used by pipe trades
journeyworkers. List the basic components
of the Dumpy Level shown in Fig. 6-8-A
and the telescope shown in Fig. 6-8-B.

 21. The information presented in the two previous
study units was designed to familiarize you with
the components of a level and a combination
transit-level. Equally as important is the need for
you to recognize that these instruments are
delicate and must be handled and used in such a
manner to prevent them from being damaged.
There are certain rules which must be followed
when setting them up or handling them. The most
important rule is to prevent falls. A fall will usually
result in the need for extensive repairs or could
destroy the instrument.

 To prevent deflection of the more delicate parts
the instrument should be handled by the base
when not on the tripod. Never stand the tripod on
a smooth surface. The legs may slip outward.
Always stand the tripod up carefully. The legs
must be wide and firm even when the setup is not
to be used for observations. The wind or a slight
touch may knock it over. Never leave the
instrument unattended unless special precautions
are made for its protection. Never subject the
instrument to vibration, which damages the
adjustments.

 Most instrument cases have large rubber
feet, which absorb vibration if the rest of
the case is free from contacts. Never force
the instrument. If the telescope or alidade
does not turn easily, do not continue to
use the instrument. Such use might
damage a bearing. What are four rules
which must be followed for an instrument
that is not being used?

 Four rules are:
 Keep the instrument in its case. This
usually guarantees protection.
 Place it in the case so that the only
contact is with the base. Keep all three
transit clamps tight. This reduces chances
for vibration. Some cases have felt-
covered contact points, which are safe.

 Keep the instrument free from dust and rapid
temperature changes. Dust nuns the finish and the
bearings. Rapid changes in temperature introduce
moisture into the telescope tube. The moisture will
fog the telescope, and the telescope must be
dismantled to remove it.
 If the instrument is wet, let it dry. Do not dry it, as
this ruins the finish and smears the glass and
graduations.

 22. Setting up an instrument is as
important to the over-all operation as any
other phase of using a combination
transit-level. The first step in setting up a
transit-level is to set up the tripod. What
are five suggestions which should be
considered when setting up an
instrument?

 Five suggestions are:
 1. Use a straight leg (nonadjustable)
tripod, if possible. See Fig. 6-9.
 2. Tripod legs should be tightened so that
when one leg is extended horizontally it
falls slowly back to the ground tinder its
own weight.

 3. When setting up the instrument, gently
force the legs into the ground by applying
weight on the tripod shoe spurs.
 4. When the tripod is to be set up on a
hillside, two legs should be placed
downhill and the third leg placed uphill.
The instrument can be set up to a roughly
leveled position by careful manipulation of
the third, uphill leg.

 5. The location of the level setup should
be chosen wisely with respect to the
ability to see the maximum number of rod
locations, particularly back-sight (B.S.) and
fore-sight (F.S.) locations.

 23. List several steps for setting up a
tripod.
 Several steps are:
 1. Loosen leg-keeper screws. See Fig. 6-
10.
 2. With tripod in closed position, adjust to
shoulder height. See Fig. 6-10.
 3. Tighten keeper screws.
 4. Loosen head wing nuts. See Fig. 6-10.

 5. Spread tripod legs, and plant them as
firmly as possible on the surface to be
used. See Fig. 6-10.
 6. Remove tripod head cap.
 7. Bring tripod head to approximately level
position. See Fig. 6-10.
 8. Tighten head wing nuts.

 24.
 After the tripod has been set up, the
instrument must be removed from its case
and attached securely to the tripod. What
is the procedure for this operation?
 As shown in Fig. 6-11, the procedure for
attaching a transit-level to a tripod is:

 1. Remove the instrument from its case,
using both hands. (Never lift the
instrument by its telescope.)
 2. Using both hands, screw the leveling
base plate of the instrument onto the
tripod head. (Care should he taken to
avoid cross threading.)

 25. After the instrument is in place on the tripod,
the protective cap over the lens must be removed.
After the cap has been removed, a sunshade may
be placed on the telescope. The motion, in both
operations, should always be clockwise. Why is a
clockwise motion used when removing the
protective cap and replacing it with a sunshade?
 A clockwise motion is used so that the lens will not
be loosened or thrown out of adjustment. See Fig.
6-12.

Material for
assignment #2
SU 26-49

 26. Before the actual leveling procedure
begins, care should be exercised to ensure
that the horizontal-motion clamp screw is
loosened. What could happen if the
telescope is turned while the horizontal-
clamp screw is in a tight or closed
position?
 Warping or, at the least, wear would occur.
Also, the locking screw might be stripped.

 27.
 What must be done with the vertical protractor
before leveling begins?
 Before leveling the instrument, the vertical
protractor must he set in a 00 position; that is, the
600 or Q0 indication is set at 00 on the vertical
circle. The vertical locking levers are then
tightened to hold this position.

 28.
 At this point, the instrument must be brought to a
level position before it is ready for actual use. Fig.
6-13-A through F shows the procedure for
leveling. A in Fig. 6-13 shows the position the
operator should assume while leveling the
instrument. Why does the operator need to stand
away from the instrument?
 Standing away from the instrument reduces the
possibility of jarring it out of the level position.

 29. Fig. 6-13-B shows the leveling screws used for
putting the telescope in a level position.
Illustrations C and D in Fig. 6-13 show the proper
position of the hands during leveling and the
proper position of the bubble when exact level is
reached. Study Fig. 6-13-E. Note the arrow heads:
two leveling screws are being turned
simultaneously in opposite directions. Why are the
leveling screws turned in this manner?

 The leveling screws must be turned in
opposite directions so that pressure is
applied to one side of the base plate and
released on the opposite side, in order to
force the telescope to move to a level
position.

 The Golden Rule for quick and simple
leveling is THUMBS IN, THUMBS OUT.
Turn BOTH screws equally and
simultaneously. Practice will help you get
the feel of the screws and the movement
of the bubble. It will also help to
remember that the direction your left
thumb moves is the direction the bubble
will move. See diagram below.

 30. Fig. 6-13-C shows the proper position of the
hands while leveling the instrument. During this
operation the telescope is lined up over two
leveling screws. Fig. 6-13-F illustrates the leveling
technique: the telescope is leveled over two
leveling screws, then turned 90° and leveled over
the remaining two screws. After the bubble in the
level vial has been centered in both positions, the
telescope should be swung 1800 in each position
to be sure the instrument will remain level in a
360° arc. Describe a procedure for sighting and
focusing the telescope.

 Aim the telescope at the object and sight first along the top of
the telescope tube. Then look through the telescope and
adjust the focus.
 When the cross hairs are positioned on or near the target,
tighten the horizontal clamp screw and make final settings
with the tangent screw to bring the cross hair exactly on
point.
 When sighting through the telescope, keep both eyes open.
You will find that this eliminates squinting, will not tire your
eyes and gives the best view through the telescope.
Remember to avoid touching the tripod while sighting.

 31. A two peg test is sometimes used to test the
accuracy of a level or transit-level. The purpose of
a two peg test is to determine if the line of sight
through the level is horizontal (parallel to the axis
of the bubble tube). The line of sight axis is
defined by the location of the horizontal cross hair
adjustment. See Fig. 6-14-A. How would a
journeyworker perform a two peg test?

 To perform the two peg test, the
journeyworker first places two stakes at a
distance of 200 feet apart. The level is set
up midway between the two stakes and
rod readings are taken at both locations.
See Fig. 6-14-B, first setup.

 If the line of sight through the level is not
horizontal, the error in the rod reading at
both points A and B will be identical as the
level is halfway between the points. Since
the errors are identical, the calculated
difference in elevation between points A
and B (difference in rod readings) will be
the true difference in elevation.

 The level is then moved to one of the points A and set up so
that the eyepiece of the telescope just touches the rod as it is
being held plumb at point A. The rod reading a, can he
determined by sighting backward through the objective lens
at a pencil point which is being moved slowly up and down
the rod. The pencil point can be centered, even though the
cross hairs are not visible. Once the reverse rod reading has
been determined, the rod is held at B and a normal rod
reading obtained. (The reverse rod reading at A will not
contain any line-of-sight error because the cross hair was not
used to obtain the rod reading.)

 32. When leveling between benchmarks or turning points,
the level is set approximately midway between the B.S. and
FS. locations to eliminate (or minimize) errors due to
curvature and refraction, and errors due to a faulty line of
sight. See Fig. 6-15-A. To ensure that the rod is plumb, either
a rod level is used, or the person holding the rod gently
“waves the rod” toward and away from the instrument. The
correct rod reading will be the lowest reading observed. The
person holding the rod must ensure that the rod does not sit
up on the back edge of the base and effectively raise the
zero mark on the rod off the B.M. (or T.P.). You can be sure
that the rod has been properly waved if the readings
decrease to a minimum value and then increase in value. See
Fig. 6-15-B. Flow would you determine the elevation at point
B in Fig. 6-15-A?

 After the rod reading of 4.71 is taken at A, the
elevation of the line of sight of the instrument is
known to be 414.97 (410.26 + 4.71). The
elevation of point B can he determined by holding
the rod at B, sighting the rod with the instrument,
and reading the rod (2.80 ft). The elevation of B is
414.97—2.80 = 412.17 ft. In addition to
determining the elevation of point B, the
elevations of any other points, lower than the line
of sight and visible from the level, can be
determined in a similar manner.

 33. Before actually using an instrument for
layout, it is necessary to become familiar
with the terms which describe some of the
operations and physical aspects of
surveying. Name the most commonly used
terms related to a surveyors instrument
for establishing line and grade.

 The terms most commonly used are:
 1. Benchmark
 2. Height of instrument
 3. Station
 4. Turning point
 5. Back-sight
 6. Fore-sight

 34. A benchmark (B.M.) is a permanent or fixed
point of known elevation. Benchmarks are
established by using precise leveling techniques
and instrumentation. Benchmarks are bronze disks
or plugs set into vertical (usually) wall faces. It is
important that the benchmark be placed in a
structure that has substantial footings (at least
below minimum frost depth penetration).
Benchmark elevations and locations are published
by federal, state or provincial, and municipal
agencies. What is a temporary benchmark
(T.B.M)?

 A temporary benchmark (T.B.M.) is a semi-
permanent point of known elevation.
T.B.M.s can be flange bolts on fire
hydrants, nails in the roots of trees, top
corners of concrete culvert headwalls, and
so on. The elevations of T.B.M.s are not
normally published but are available in the
field notes of various surveying agencies.

 35.
 Define station as it is used in surveying.
 Station is a definite position or point:
 a) The points between which a measured
length occurs are stations.
 b) Any point used as an instrument point
is also a station.

 36.
 In the event a benchmark is not visible from a
point which is to be used on a particular
installation, other intermediate points must be set
up temporarily to transfer the known elevation to
a suitable location. What are these intermediate
points called?
 These intermediate points, temporarily used for
transferring a known elevation, are called turning
points. See Fig. 6-16.

 37. When a turning point (T.P.) must be
utilized, there are two distinct sightings
necessary to its correct application. What
is the first sighting necessary in the use of
a turning point?
 First, the instrument, in the level position,
is directed toward the benchmark and a
measurement is taken from the projected
level plane.

 This measurement is called a back-sight.
Back- sight (B.S.) is a rod reading taken
on a point of known elevation in order to
establish the elevation of the instrument
line of sight.

 38. Why is a back-sight reading always
used as a plus-sight?
 A back-sight is always used as a plus-sight
be cause a back-sight is always added to
the known elevation in order to establish
the height of the instrument.

 39. The second sighting necessary in the use of a
turning point is called a fore-sight. What is the
purpose of a fore-sight?
 A fore-sight, taken with the instrument in the level
position and directed away from the benchmark,
establishes another elevation in relation to the
benchmark. Fore-sight (F.S.) is a rod reading taken
on a turning point, benchmark, or temporary
benchmark in order to determine its elevation.

 40. A fore-sight is always used as a minus-
sight because it is always subtracted from
the instrument height. What does a fore-
sight reading produce?
 A fore-sight reading subtracted from the
instrument height produces another
benchmark.

 Example: Original benchmark (B.M.) ÷
back- sight (U.S.) = instrument height.
Instrument height (HI.) — fore-sight (F.S.)
= elevation of turning point (T.P.), new
benchmark (B.M.) or temporary
benchmark (T.B.M.).

 41. Elevations from a projected level plane are
established by measuring from the projected plane
to the surface below the plane. By what means is
this accomplished?
 The measurement from a projected level plane to
a surface can be read on a rod that has markings
in hundredths of a foot, a six-foot rule, or simply a
piece of wood which is marked and measured
later.

 42. Several devices are used by
joumeyworkers to measure from a
projected horizontal plane. One of the
most versatile and widely used devices is
the Philadelphia extension rod. What are
some of the features of the Philadelphia
rod?

 Some of the features are:
 1. In most cases it can be easily read by
the journeyworker because the
graduations are large and legible.
 2. Because it incorporates an extension
rod, more readings can be taken without
changing the instrument height.

 3. A target can be affixed to a Philadelphia
rod if, because of distance or intervening
areas of inaccessibility such as bodies of
water, the journeyworker cannot read the
rod.

 43. Fig. 6-17 shows a Philadelphia rod
with the rod extended. A target gives the
journeyworker a larger object to sight on.
Fig. 6-18 shows a target as seen through
the instrument. When is a target used,
and what purpose does it serve?

 A target is used when the rod is too far
away to be read accurately by the
journeyworker. It is attached to the rod,
and when the target is bisected by the
cross hair on the instrument, it is in the
correct position to be read by the rod
man.

 44. An enlarged section of a rod is shown
in Fig. 6-19. The red numbers designate
feet. The smaller black numbers on the
rod designate tenths of a foot. What is the
correct reading for the red line shown in
Fig. 6-19?
 The red line in Fig. 6-19 designates 5.100’,
or five feet and ten one-hundredths of a
foot.

 45. Fig. 6-20 shows three instrument
sightings on a rod. The white spaces are
one hundredth of a foot wide, and the
black markings are one hundredth of a
foot wide. What are the correct instrument
readings in Fig. 6-20?
 The correct readings in Fig. 6-20 are:
 A = 10.93’, B = 4.79’ C = 4.03’

 46. Prior to taking rod readings, the cross
hair should be sharply focused; it helps to
point the instrument toward a light-
colored background. List four additional
factors which should be considered prior
to taking rod readings.

 Four additional factors are:
 I. When the journeyworker observes apparent
movement of the cross hairs on the rod, the cross
hair focus adjustment and the objective focus
adjustment should be carefully checked for
consistent results.
 2, The journeyworker should consistently read the
rod at either the top or the bottom of the cross
hair.

 3. Never move the level before a fore-
sight is taken; otherwise, all work done
from the HI. will have to be repeated.
 4. Rod readings (and the line of sight)
should be kept at least 18’ above the
ground surface to help minimize refraction
errors.

 47. In some instances, when the rod is being read
through the instrument, the foot designation may
not be visible. Fig. 6-21 illustrates an instrument
sighting where the foot figure is outside the view.
How can the journeyworker get the proper
reading?
 To get the proper reading, the journeyworker
must have the rod raised slowly until the nearest
red foot designation can be seen through the
telescope.

 48. Assuming that the surface elevation of the ground
is 107.94 feet and the invert elevation of a pipeline at
this point is 102.33 feet, how deep is the pipeline from
the surface of the ground to its invert? (Invert
elevation is the elevation of the inside bottom of the
pipe to be installed.)

 49. Mistakes in leveling and invert
elevations of a pipeline can be detected by
performing arithmetic checks and also by
closing in on the starting B.M. or on any
other B.M. whose elevation is known.
Explain.

 Mistakes in rod readings that do not form
part of a level loop, such as intermediate
sights taken in profiles, cross sections, or
pipeline grades, are a much more serious
problem.
 Since most intermediate rod readings
cannot be inherently checked, it is
essential that the potential for mistakes he
minimized.

 Common mistakes in leveling include the
following: misreading the foot value; transposing
figures; not holding the rod in the correct location;
resting the hands on the tripod while reading the
rod and causing the instrument to go off level;
entering the rod readings incorrectly (switching
B.S. and ES.); giving a correct rod reading with
the wrong station identification; and mistakes in
note reduction arithmetic.

 Mistakes in arithmetic can be largely
eliminated by having other journeyworkers
check the reductions and initial each page
of notes checked. Mistakes in the leveling
operation cannot be totally eliminated, but
they can be minimized if journeyworkers
are aware that mistakes can (and probably
will) occur.

Chapter 6 Part 2
Instruments in the Piping Trade

Instruments for Piping Layout
Material for
Assignment #3
Study Units 50-79

 50. Reading a rod or working with
elevations requires knowing how to
convert hundredths of a foot to inches and
inches to hundredths of a foot. Convert
5.61’ to feet and inches, to the nearest
eighth of an inch.

 All units to the left of the decimal point
represent feet because the complete
number 5.61 is read as, five and sixty-one
hundredths of a foot. To convert .61’ to
inches, multiply .61’ by 12”.

 51. Sometimes it may be more convenient
to refer to a table than to convert the
hundredths of a foot to inches and
fractional parts of an inch. A simple table
may be constructed by graduating a foot
by intervals of an eighth of an inch in six
columns. How is this table constructed?

 Using .01 = 1/8” as a starting point,
construct four columns of twenty-five
items each, leaving the sixteenth item in
each column with no inch equivalent, as
shown in Table 6-1. Each item advances
by both 1/100’ and 1/8”. This table is
accurate to the nearest eighth of an inch.
In excavation for, or the installation of a
pipeline, an eighth of an inch is sufficiently
accurate for the work.

 52. Laying out for the excavation and
installation of an underground piping
system is a process involving a number of
steps. This process is generally referred to
as laying out line and grade. Establishing
the line is the first step. How is line
established?

 Line is established by transferring the
indicated location of the pipeline to be
installed from the drawings to its actual
physical location on the job site.

 53. In order to transfer the location of the
pipeline from the drawings to the job site, it is
necessary to know where the line is located in
relationship to the building or structure being
serviced, and the angles formed as it leaves the
structure and travels to its main source of supply
or distribution. Fig. 6-22 shows a 6’ pipeline
leaving a structure and running to a 10” sewer
main in a roadway. What is the first step in
locating the building line on the job site?

 If no dimension is given on the drawing,
the location of the building line is scaled
from the nearest parallel building line.

 54. In Fig. 6-22, the pipe line leaves the
structure, by scale, 30’ west of the east
building line. The line runs from the
building to manhole A. Using a protractor
on the drawing, it can be established that
the line in Fig. 6-22 leaves the building at
a ninety degree angle to the north
building wall. How is manhole A in Fig. 6-
22 located?

 Fig. 6-23 illustrates the use of the 3-4-5 triangle
to establish a perpendicular line. In Fig. 6-23, 3-
4-5 proportions have been multiplied by 3 in
order to establish a point at a reasonable
distance from the north building line. The 12’
and 15’ measurements intersect at point X, to
establish the end of a line that lies 90° to the
building wall. The center line (CL) manhole A is
then located by scaling the drawing for its
distance from the north building line and then
measuring this distance along the 90° line
already laid out,

 55. The distance along the 900 line can be measured
with a steel tape shown in Fig. 6-24 or an engineer’s
chain (long tape) usually 100 feet in length similar to the
one shown in Fig. 6-25. The most popular steel tapes
(100 ft) now in use require a normal tension of about 24
lb. For most (100 ft) steel tapes now in use
(lightweight), a normal tension of 20 lb is appropriate.
Random errors are sometimes associated with
alignment, marking and plumbing to a mark with a
plumb bob. What are some common mistakes
encountered when using a tape or an engineers chain?

 Some common mistakes are:
 1. Measuring to or from the wrong marker.
Journeyworkers must be vigilant to ensure that
measurements begin or end at the appropriate
permanent or temporary marker. Markers
include construction stakes or bars, nails, and
the like.
 2. Reading the tape incorrectly. It sometimes
happens that mistakes are made by reading.
Transposing figures is a common mistake
(reading 56 instead of 65).

 3. Losing proper count of the full tape lengths
involved in a measurement.
 4. Recording the values in the notes incorrectly.
It sometimes happens that the journeyworker
will hear the callout correctly but then transpose
the figures as they are being entered in the
notes. This mistake can he eliminated if the
journeyworker calls out the value as it is
recorded. The journeyworker listens for this
callout to ensure that the values called out are
the same as the data originally given.

 5. Calling out values ambiguously. The
journeyworker can call out 20.27 as twenty
(pause) two, seven. This might be interpreted as
22.7. To avoid mistakes this value should be
called out as twenty, decimal (point), two,
seven.
 6. If using cloth or fiberglass tapes, the zero
point of the tape is often not identified correctly.
This mistake can be avoided if the
journeyworker checks unfamiliar tapes before
use. The tape itself can be used to verify the
zero mark.

 7. Arithmetic mistakes can exist in sums of
dimensions and in error corrections for
slope. These mistakes can be identified
and corrected if each journeyworker is
responsible for checking (and signing) all
notes.

 56. In order to continue the building line
in Fig. 6-22 from manhole A to the main in
the roadway, the angle of its change of
direction at manhole A must be
established. How is this done if the angle
is not given?
 If an angle is not given on a drawing, it
can be established by using a protractor
on the drawing.

 57. Fig. 6-26 shows the angle of the
pipeline at manhole A to be 120. How can
this angle be laid out by using a
combination transit and level?
 This angle can be laid out by setting up
the instrument in a level position directly
over the point where the line changes
direction and turning the angle required.

 58. What is the procedure which should
be used to turn an angle with an
instrument?
 The procedure is:
 1. The degree of the angle of change
must he determined.
 2. The point where the change of direction
is to originate is laid out.

 3. The instrument is set up level, directly
over the point where the change
originates, as established by a plumb bob
attached to a chain which passes through
the tripod head. See Fig. 6-27.
 4. A back-sight is taken along a portion of
the line to a point already established, and
the instrument is then locked to this
position.

 5. The horizontal protractor on the
instrument is set at 0-0, as shown in Fig.
6-28.
 6. The instrument is unlocked, turned until
the number of degrees of the change
shows on the indicator as illustrated in Fig.
6-29, and locked in this position.

 7. With the instrument in this position, a
point is laid out.
 Note: In Fig. 6-29, the angle turned is
120°. The horizontal circle is divided 00 to
90° to 0°. The 120° angle is made by
turning from 0° to 90°, then 30° past 90°,
that is, to 60° on the second scale.

 59. How is the angle turned when setting up for
a branch line connection at a manhole?
 Fig. 6-30 is a sketch of a 4” branch line
connecting at a 40° angle to the main line at a
manhole. The instrument should be set up in
level position at the point of intersection. With
the instrument in transit position, a sighting is
taken on the reference point. The horizontal
protractor is then set at 0-0 and the angle
turned. A new point is then established at Y in
Fig. 6-30.

 60.
 Turning an angle is done with the
instrument in the transit position — with
the vertical locking levers open — in order
to sight a reference point or a new point.
What must be done before sighting a
point?
 The instrument must be set up in a level
position.

 61. When sighting a point, turning an
angle, or taking any sight, it requires the
vertical cross hair in the telescope lens to
be in exact alignment with an object. How
is the instrument adjusted to bring the
vertical cross hair into alignment?

 Fig. 6-31 shows the locking screw which
stops the horizontal movement of the
instrument. The screw directly above and
to the right of the locking screw is the
fine-adjustment screw which moves the
telescope to the right or left in a slow,
precise manner.

 62. Focusing the telescope requires two
adjustments: The cross hairs of the
telescope must be brought into sharp
focus, and the object being sighted must
also be sharply focused. How are these
adjustments made on the telescope?

 The knob on top of the telescope, as
shown in Fig. 6-32, adjusts the focus on
the object being sighted.
 The eye piece on the rear of the telescope
brings the cross hairs into sharp focus.
See Fig. 6-33.

 63. Fig. 6-34 shows three positions on an
instrument protractor. What are the
readings shown in Fig. 6-34-A, B and C, to
the nearest degree?

 64. The second step in laying out line and
grade is establishing the proper depth, or
elevation, of the pipe to be installed. The
pipe to be discussed here is the 6”
pipeline mentioned in preceding study
units. What information must be known
before grade (total fall of the pipeline) can
be computed?

 The information which must be known
before grade (total fall) can be computed
is: the invert elevation of the pipe at its
source of supply or distribution; if grade is
required it is necessary to know the grade
in inches per foot or the percent of grade;
and the elevation of the benchmark, on
which other elevations are to be based.

 65. Line has already been established for the 6”
pipeline shown in Fig. 6-35. Assume that no job
site benchmark has been provided. Therefore, a
benchmark must be established based on a
permanent location set by the U.S. Coast and
Geodetic Survey or other authorized agency. Fig.
6-36 shows such a benchmark. How can the
benchmark in Fig. 6-36 be used to establish a
job site benchmark?

 The exact elevation of the permanent
benchmark No. 1040, shown in Fig. 6-36,
must he obtained from the National
Geodetic Survey or other authorized
agency. If the exact elevation, in relation
to sea level, is not available for a
particular job, an arbitrary elevation such
as 100.00 can be assigned.

 66. What type of information is available for
making use of a permanent benchmark?
 Location maps showing permanent benchmarks
are available through local agencies. Fig. 6-37, a
typical location map, includes benchmark No.
1040 (see arrow). The actual elevation and
coordinates for a benchmark line No. 1040 are
furnished on a separate information sheet, also
available from local agencies.

 67. Fig. 6-38 is a plot plan showing an
existing building and benchmark No. 1040,
located south and west of an existing
building. The proposed building is located
a considerable distance from the
permanent benchmark. What must be
done to establish a job site benchmark for
the proposed building?

 Because of the obstructions between the
permanent benchmark and the proposed
building, a series of turning points must
be set up to establish a known elevation
at the job site.

 68. The elevation of benchmark No. 1040
in Fig. 6-38 is 870.16 feet. What does an
elevation of 870.16 feet represent?
 An elevation of 870.16 represents the
distance above mean sea level to
benchmark No. 1040, as shown in the
profile drawing in Fig. 6-39 on page 140.

 69. In Fig. 6-40 on page 141, two turning
points and three instrument locations have
been selected in order to establish a job
site benchmark. What factor must be
considered when choosing an instrument
location?
 An instrument location must provide an
unobstructed view of a known elevation.

 70. What does the back-sight from
instrument location A, in Fig. 6-40,
produce?

 Back-sight is always a plus-sight reading
which is added to a known elevation. The
back-sight (B.S.) from any instrument
location plus the elevation of the point
sighted produces the elevation of the
instrument. The B.S. is a rod reading
taken on a point of known elevation in
order to establish the elevation of the
instrument line of sight.

 71. What is the term given to the
elevation of the instrument?
 The elevation of the instrument is known
as “height of instrument” or “H.I.” It is the
elevation of the line of sight through the
level (elevation of B.M. + B.S. = HI.).

 72. With the instrument in a level position
at location A in Fig. 6-40, what is the H.I.
if the back- sight or “B.S.” reading is 10.26
feet?
 B,S. is always added to a known elevation.
Location A back-sight (10.26) is added to
B.M. No. 1040 elevation (870.16’)
establishing the H.I. as 880.42’.

 73. As stated in Study Unit 72, the HJ. is
now a known elevation of 880.42 feet. If a
fore-sight (ES.) reading is taken at turning
point (T.P.) #1 of 2.35 feet, what is the
elevation at turning point #1?
 F.S. 2.35’ subtracted from known elevation
HI. of 880.42 equals 878.07’. The
elevation at T.P. #1 is 878.07.

 74. The U.S. from instrument location B in
Fig. 6-40 produces a second height of
instrument at instrument location B. The
B.S. reading from location B is 1.78 feet.
What is the H.I. at location B, and how is
it computed?
 H.I. at location B = 879.85’ because B.S.
1.78 is added to the TI’. #1 elevation of
878.07’.

 75
 The BS. reading from instrument location
B in Fig. 6-40 is 1.65 feet. What is the
elevation at T.P. #2?
 TP. #2 elevation = 878.20’.

 76.
 Instrument location C has a B.S. reading
of 9.84 feet. What is the H.I. at
instrument location C?
 H.I. elevation at location C = 888.04’.

 77. In Fig. 6-40, the final reading from
instniment location C is a ES. reading of 6.09
feet. What is the elevation of the job site
benchmark established by this reading?

 78. In Fig. 6-40, the transferring of known
elevations required a series of several
steps. What should be done to work out
these steps in an accurate, logical order?
 A work sheet such as shown in Fig. 6-41
should be used for accurately and logically
completing each of the steps required to
transfer the known elevations.

 79. Fig. 6-42 shows a typical record of field
notes taken from the work sheet in Fig. 6-41.
Although the form of records vary, it is important
to keep good records of work in the field. Why
are good field records important?
 If it should become necessary to go back on a
job and re-excavate an underground pipe, good
field records are invaluable in locating a piping
system.

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