Calculated Industries 4090 User Manual

SHEET METAL HVAC PRO

Model 4090

User’s Guide

INTRODUCTION

The custom-designed ITI Sheet Metal/HVAC Pro calculator was
specifically created for sheet metal pro’s to ease the task of perform­ing mathematics on the job. It includes the most popular built-in for­mulas for sheet metal computations, so you’ll save time, increase
accuracy and eliminate errors.

Your Calculator Helps You Solve:

• Dimensional Math Problems

• Conversions Between Feet-Inch-Fractions, Decimal Feet,
Decimal Inches and Metric

• Problems Involving All Common Fractions – 1/2” to 1/64”

• Area/Volume Calculations

• Arc/Circle/Column/Cone Areas and Volumes

• D:M:S

• Scientific Notation, Cubed Root

• Offset Calculations

• Trigonometry

• Law of Cosines

• Fan Laws 1, 2 and 3

• Velocity/Velocity Pressure Conversions

• Right Angle/Rafter Solutions

• Stair Layout (Risers/Treads), and more!

It also includes handy construction math and material estimation
examples — such as right angle/rafter and stair calculations — that
will also help you build faster and more accurately.

USER’S GUIDE —1

TABLEOFCONTENTS

KEY DEFINITIONS ............................................................................6

BASIC OPERATION KEYS .............................................................6

CONVERT Ç KEY—UNIT CONVERSIONS and

SECOND FUNCTIONS................................................................6

MEMORY and STORAGE FUNCTIONS ........................................7

RECALL ® KEY ..........................................................................8

FEET-INCH-FRACTION and METRIC KEYS .................................8

TRIGONOMETRIC KEYS ...............................................................9

PYTHAGOREAN THEOREM/RIGHT TRIANGLE KEYS ..............10

LAW OF COSINES/NON-90 DEGREE TRIANGLE KEYS ...........12

OFFSET KEYS..............................................................................13

FAN LAW KEYS ............................................................................14

VELOCITY PRESSURE/FPM KEYS ............................................15

CIRCULAR/ARC FUNCTION KEYS .............................................15

COLUMN/CONE KEY ...................................................................16

HIP/VALLEY and JACK RAFTER KEYS.......................................17

STAIR KEY....................................................................................19

GETTING STARTED........................................................................21

ORDER OF OPERATIONS ...........................................................21

USING PARENTHESES ...............................................................22

SETTING FRACTIONAL RESOLUTION.......................................23

Setting Fraction Resolution to Other Than 16ths —

Using the Preference Setting Mode .......................................23

Setting Fixed/Constant Fractional Resolution............................24

ENTERING DIMENSIONS............................................................25

Entering Linear Dimensions.......................................................25

Entering Square/Cubic Dimensions...........................................25

CONVERSIONS (LINEAR, AREA, VOLUME) ..............................27

Linear Conversions ....................................................................27

Converting Feet-Inch-Fractions to Decimal Feet.......................27

Converting Decimal Feet to Feet-Inch-Fractions.......................27

Converting Fractional Inches to Decimal Inches .......................27

Converting Decimal Inches to Fractional Inches .......................28

Square Conversions ..................................................................28

Cubic Conversions.....................................................................28

PERFORMING BASIC MATH WITH DIMENSIONS....................29

Adding Dimensions ....................................................................29

Subtracting Dimensions .............................................................29

Multiplying Dimensions ..............................................................29

2—ITISHEET METAL/HVAC PRO

Dividing Dimensions ..................................................................29

Percentage Calculations ............................................................30

MEMORY OPERATION ................................................................31

EXAMPLES — USING THE SHEET METAL/HVAC PRO ..............33

BASIC EXAMPLES .......................................................................34

Adding Linear Measurements....................................................34

Converting Feet-Inch-Fractions to Decimal Feet and

Fractions of an Inch................................................................34

Converting Feet-Inches to Meters and Millimeters ....................34

Adding and Subtracting Fractions of an Inch.............................35

Converting Fractions to Decimals..............................................35

Converting Decimals to Fractions..............................................35

Finding Length (of Iron) Required..............................................35

Circumference of a Circle ..........................................................36

Circumference and Area of a Circle...........................................36

Square Area (x

2

).........................................................................36

Area of a Rectangle ...................................................................36

Area of a Triangle ......................................................................37

Volume of a Rectangular Box ....................................................37

Volume of a Rectangular Container, Converting to

Cubic Meters...........................................................................37

Volume of a Cylinder..................................................................38

Volume of a Cone ......................................................................38

Cubed Function..........................................................................39

Cubed Root Function.................................................................39

Scientific Notation ......................................................................39

TRIGONOMETRIC FUNCTIONS..................................................40

Finding Sine, Cosine, Tangent...................................................41

Finding “Angle A” (ArcSin, ArcCos, ArcTan) ..............................41

Using Trigonometry to Find Unknown Side ...............................41

Using Trigonometry to Find Unknown Angle or Side .................42

Converting Pitch to Angle/Tangent.............................................45

D:M:S EXAMPLE ..........................................................................45

Converting Degrees:Minutes:Seconds ......................................45

VELOCITY PRESSURE/VELOCITY EXAMPLES.........................46

Converting Velocity Pressure to FPM ........................................46

Converting FPM to Velocity Pressure ........................................47

OFFSET EXAMPLES ....................................................................48

Offset, Basic Example................................................................48

OGEE Offset in Feet-Inch-Fractions ..........................................49

OGEE Offset, in Millimeters .......................................................50

USER’S GUIDE —3

Dividing Offset into Multiple Degreed Elbows for

Manageable Sections .............................................................51

Change OGEE Offset ................................................................53

LAW OF COSINES EXAMPLES ...................................................55

Field Measuring for Ductwork Using the Law of Cosines

Introduction .............................................................................55

Non-90 Degree Triangle Measurement Using Law of Cosines

and Heron’s Theorem .............................................................56

Using Law of Cosines and Pythagorean Theorem to

Calculate Offset, Length, and Angle.......................................58

Sheet Metal Panels for an Irregular Hip Roof............................59

Inline Duct, Single Offset (Computing Offset, Length,

and Angle)...............................................................................60

Inline Duct, Double Offset (Computing Offset, Length,

and Angle)...............................................................................62

Objects at Right Angles .............................................................65

Calculating Angles Between Objects (“Angle Between”)...........69

Calculating Angles Between Objects Example ..........................70

FAN LAW EXAMPLES ..................................................................75

Fan Law 1 ..................................................................................75

Fan Law 2 ..................................................................................76

Fan Law 3 ..................................................................................77

ARC/CIRCLE EXAMPLES ............................................................78

Arc Length — Degree and Diameter Known .............................78

Arc Length — Degree and Radius Known.................................78

Using ArcK to Calculate an Arc Length......................................78

Arc Calculations — Arc Length and Diameter Known...............79

Arched/Circular Rake-Walls — Chord Length and Segment

Rise Known.............................................................................80

Arched Windows ........................................................................81

CONCRETE/PAVING ....................................................................82

Squaring-up a Foundation .........................................................82

Volume of a Rectangle...............................................................82

Volume of Columns....................................................................83

RIGHT TRIANGLE and ROOF FRAMING EXAMPLES ...............84

Roof Framing Definitions ...........................................................84

Degree of Pitch ..........................................................................86

Percent Grade............................................................................86

Common Rafter Length..............................................................87

Common Rafter Length — Pitch Unknown................................87

Angle and Diagonal (Hypotenuse).............................................88

4—ITISHEET METAL/HVAC PRO

Rise ............................................................................................88

Rise and Diagonal......................................................................88

Sheathing Cut ............................................................................89

Regular Hip/Valley and Jack Rafters .........................................89

Jack Rafters — Using Other Than 16 Inch On-Center

Spacing...................................................................................91

Irregular Hip/Valley and Jack Rafters — Descending, with

On-Center Spacing Maintained ..............................................92

STAIR LAYOUT EXAMPLES ........................................................94

Stair Layout Definitions ..............................................................94

Stairs — Given Only Floor-to-Floor Rise ...................................96

Stairs — Given Only the Run.....................................................98

Stairs — Given Rise and Run....................................................99

Baluster Spacing......................................................................100

APPENDIX A — TRIGONOMETRY FORMULAS .........................101

APPENDIX B — AREA/VOLUME FORMULAS............................102

AREA FORMULAS......................................................................102

SURFACE AREA/VOLUME FORMULAS ...................................103

APPENDIX C — OFFSET FORMULAS ........................................104

APPENDIX D — LAW OF COSINES/HERON’S THEOREM

FORMULAS ................................................................................105

APPENDIX E — FAN LAW FORMULAS ......................................106

APPENDIX F — DEFAULT SETTINGS.........................................106

APPENDIX G — PREFERENCE SETTINGS................................107

How to Set Preferences ..............................................................110

Accessing Preference Settings....................................................111

APPENDIX H — CARE INSTRUCTIONS......................................113

APPENDIX I — ACCURACY, AUTO SHUT-OFF, BATTERIES,

ERRORS .....................................................................................114

Accuracy/Errors ...........................................................................114

Auto Shut-Off...............................................................................115

Battery(ies) ..................................................................................115

Replacing the Battery(ies) ...........................................................115

Battery Replacement Instructions ...............................................115

Reset Key ....................................................................................115

REPAIR AND RETURN..................................................................116

WARRANTY...................................................................................117

INDEX.............................................................................................119

USER’S GUIDE —5

KEY DEFINITIONS

BASIC OPERATION KEYS

o

O

+–x Arithmetic operation keys.
÷=

Ç+ Percent (%) — Four-function percent. See page 30

0 – 9 and • Keys used for entering digits.

B Backspace Key — Used to delete entries one key-

On/Clear — Turns power on. Pressing once clears the
display. Pressing twice clears all temporary values.

Turns all power off, clearing all non-permanent registers.

for examples.

stroke at a time (unlike the o function, which
deletes the entire entry).

CONVERT Ç KEY —

UNIT CONVERSIONS and SECOND FUNCTIONS

The Ç key is to convert between measurement units or to access
second functions, listed below:

Ç Convert — Used with the measurement keys to

convert between units or with other keys to access
special functions.

Çx Clear All — Clears all values, including Memory.

Resets all permanent entries to default values
(except Preference Settings, which are retained).

Note: Use only when necessary, as it deletes all stored values.

X Squares the value in the display. For example, to

Square the value ten, enter 10then press X.

ÇX x3— Cubes the value in the display. For example, to

Cube the value ten, enter 10then press ÇX.

√ Square Root Function — Used to find the Square

Root of a non-dimensional or area value
(e.g., 100√=10).

6—ITISHEET METAL/HVAC PRO

Ç√ Cube Root Function — Used to find the Cube Root

of a non-dimensional or area value (e.g., 100
0Ç√= 10).

y

Ç/ x10

— Allows entry of an exponent. For example,

8Ç/14is 8 times 10 to the 14th power
(8x1014).

Ç÷ 1/x — Finds the reciprocal of a number (e.g., 8

Ç÷= 0.125).

Ç– Change(+/–)Sign— Changes the sign of the dis-

played value to negative or positive.

π Pi — Constant = 3.141593

Çπ ArcK — Constant = 0.017453. This value is equiva-

lent to the constant of a 1° arc angle for a one-unit
value. The formula for this constant is π ÷ 180.

Ç• Degrees:Minutes:Seconds — Converts between

D:M:S and Decimal Degree formats.

Note: Your calculator uses a floating d:m:s format (that is, dis­plays decimal degrees to the maximum number of decimal points,
for greater accuracy). If you desire rounding to two decimal points
(0.00°), you must set your calculator via Preference Settings (see
page 107).

Ç= Access Preference Settings — Used to access

various customizable settings, such as dimensional
answer formats (see Preference Settings on page

107).

MEMORY and STORAGE FUNCTIONS

Your calculator has two types of Memory:

1) basic Memory or Semi-Permanent, Cumulative μ;

2) non-cumulative Storage Registers (M1-M3).

μ Semi-Permanent Memory — Adds any displayed

number, dimensioned or unitless, to the semi-per­manent, accumulating Memory. Values can be sub­tracted from this Memory using Çμ. ®®
will recall and clear the Memory. Ǯwill swap
the value stored in accumulative Memory with the
value that is currently displayed.

USER’S GUIDE —7

Ç1 Storage Register (M1) — Stores the displayed

value in non-cumulative, permanent Memory (e.g.,
10Ç1, ®1= 10). Good for storing a
single value, for future reference.

Note: Non-cumulative means it only accepts one value (does not
add or subtract) and a second entered value will replace the first.
Permanent means the value is stored even after the calculator is
shut off. To delete a stored value, enter a new value or perform a
Clear All (Çx).

Ç2 Storage Register (M2) — Same function as Ç

1. See above.

Ç3 Storage Register (M3) — Same function as Ç

1. See above.

RECALL ® KEY

The ® key is used to recall or review stored values (e.g., ®p
to recall a previously entered pitch value). It is also used in review­ing stored settings and Memory operation (see below).

®® Clear M+ — Displays and clears M+.

®μ Recall M+ — Displays value stored in M+.

®1 Recall M1 — Recalls the stored value in M1.

®2 Recall M2 — Recalls the stored value in M2.

®3 Recall M3 — Recalls the stored value in M3.

FEET-INCH-FRACTION and METRIC KEYS

The following keys are used for entering units of measure, with ease
and accuracy:

f Enters or converts to Feet. Also used with the i

and / keys for entering Feet-Inch values (e.g., 6
f9i1/2).

Note: Repeated presses after Ç toggle between Feet-Inches and
Decimal Feet (e.g., 6f9i1/2Çf= 6.791667
FEET; press f again to return to Feet-Inch-Fractions).

8—ITISHEET METAL/HVAC PRO

i Enters or converts to Inches. Also used with the /

key for entering fractional inch values (e.g., 9i
1/2).

Note: Repeated presses after Ç toggle between Fractional
and Decimal Inches (e.g., 9i1/2Çi=9.5
INCH; press i again to return to Inch-Fractions).

/ Fraction Bar — Used to enter Fractions. Fractions

may be entered as proper (1/2, 1/8, 1/16) or improper
(3/2, 9/8). If the denominator (bottom) is not entered,
the calculator's fractional resolution setting is auto­matically used (e.g., entering 15/=or +
will display 15/16, based on the default fractional
resolution setting of 16ths.

m Meters — Enters or converts to Meters.

Çm Millimeters — Enters or converts to Millimeters.

TRIGONOMETRIC KEYS

Tangent Ø = Opposite

Adjacent

Sine Ø = Opposite

Hypotenuse

Cosine Ø = Adjacent

Hypotenuse

USER’S GUIDE —9

Your calculator has standard trigonometric keys, in addition to Right
Triangle keys (e.g., R, r, d and p), for advanced Right Triangle
mathematics.

The Sine, Cosine, and Tangent of an angle are defined in relation to
the sides of a Right Triangle.

Using the Ç key with the trigonometric function gives you the
Arcsine, Arccosine and Arctangent – all of which are used to find the
Angle for the Sine, Cosine, or Tangent value entered.

S Sine Function — Calculates the Sine of a Degree

or undimensioned* value.

ÇS Arcsine (sin

-1

) — Calculates the angle for the

entered or calculated Sine value.

ç Cosine Function — Calculates the Cosine of a

Degree or undimensioned* value.

-1

Çç Arccosine (cos

) — Calculates the angle for the

entered or calculated Cosine value.

t Tangent Function — Calculates the Tangent of a

Degree or undimensioned* value.

Çt Arctangent (tan

-1

) — Calculates the angle for the

entered or calculated Tangent value.

*Note: Cannot use on dimensioned values.

PYTHAGOREAN THEOREM / RIGHT TRIANGLE KEYS

10 — ITI SHEET METAL/HVAC PRO

Using the Pythagorean Theorem, the top row of keys on your ITI
Sheet Metal/HVAC Pro provides instant solutions in dimensional format

to Right Triangle problems for sheet metal problems and roof framing.

The Right Triangle is calculated simply by entering two of four variables:

1) x (Run)

2) y (Rise)

3) r (Diagonal, or Hypotenuse); or

4) θ (Theta/Pitch).

R Run — Enters or calculates “x,” or the Run or hori-

zontal leg (base) of a Right Triangle.

r Rise — Enters or calculates “y,” or the Rise or verti-

cal leg (height) of a Right Triangle.

d Hypotenuse or Diagonal (for Roof Framing) —

Enters or calculates the Hypotenuse or diagonal leg
of a Right Triangle. Typical applications in construc­tion/framing are “Squaring-up” slabs or finding
Common rafter lengths. Additional presses of the d
key will also display Plumb and Level cut angles in
degrees.

Note: The Common rafter calculation is the “point-to-point” length
and does not include the overhang or ridge adjustment.

p Theta — Enters or calculates the Pitch (slope) of a

roof (or Right Triangle). Pitch is the amount of “Rise”
over 12 Inches of “Run.” Pitch may be entered as:

• a Dimension: 9ip

• an Angle or Degrees: 30p

• a Percentage (percent grade): 75Ç+p

Once a Pitch in one of the above formats is entered,
consecutive presses of p will convert to the remain­ing pitch formats listed above (e.g., Pitch in Inches
will convert to Pitch Degrees, Percent Grade and
Pitch Ratio/Slope).

Note: An entered (vs. calculated) Pitch is a permanent entry. This
means that it will remain stored even after you turn the calculator
off. To change the Pitch, simply enter a new Pitch value.

In contrast, a calculated Pitch value is not permanently stored.
This means that the calculator will return to the Pitch value you
last entered when you press o twice.

USER’S GUIDE —11

LAW OF COSINES / NON-90 DEGREE TRIANGLE KEYS

Ç9 Law of Cosines — These keys are used for non-90

degree triangle mathematics and are incorporated
with Right Triangle mathematics (using “Measured”
non-90 degree and “Calculated” Right Triangles),
particularly, for finding the dimensional relationship
of distance and alignment between two or more
objects. The overall purpose of these calculations is
to develop the duct and/or fittings required to fill a
space.

These keys calculate the opposite angles A, B, and
C given entry of Side a, b, and c using the Law of
Cosines (see Storage Registers a, b, and c below)
and triangle area using Heron’s Theorem. They also
enable the computation of Right Triangle lengths “x,”
“y,” “r ” and Theta, for determining Offset, Length,
and Angle.

Press

1 Angle A
2 Angle B
3 Angle C
4 Area (using formula for Heron’s Theorem)
5 Redisplays entered Side a
6 Redisplays entered Side b
7 Redisplays entered Side c

Ç4 Storage Register “a” — Enters Side “a” of a

Measured Triangle (e.g., if Side “a” is five feet, enter

5fÇ4).

Ç5 Storage Register “b” — Enters Side “b” of a

Measured Triangle.

Ç6 Storage Register “c” — Enters Side “c” of a

Measured Triangle.

12 — ITI SHEET METAL/HVAC PRO

Result

Right Triangle Functions:

R Length of Unknown Side — Calculates Side “x” of

unknown Right Triangle.

r Length of Unknown Side — Enters Side “y” of

unknown Right Triangle.

d Hypotenuse — Enters “c” of Measured Triangle as

“r” of unknown Right Triangle, for final determination
of “x” and “y.”

p Theta — Finds unknown angle for determination of

“x” and “y.”

OFFSET KEYS

Ç( Offset — Calculates offset measurements, including

the Centerline Radius, Wrapper Length/Stretch-out,
Heel Radius, Throat Radius and Theta, given entry
of “x” (actual length), “y” (offset), and “a” (“end a”)
into the keys below:

Press

1 Centerline Radius (CR)
2 Wrapper Length/Stretch-out (WL)
3 Heel Radius
4 Throat Radius
5 Theta (THET)
6 Redisplays entered “x” (Actual Length)
7 Redisplays entered “y” (Offset)
8 Redisplays entered “a” (Storage

R Actual Length — Enters the actual length “x” for

offset calculations.

r Offset Length — Enters the offset “y.”

Ç4 Storage Register “a” — Enters length of “end a”

for offset calculations.

Result

Register “a” or End “a”)

USER’S GUIDE —13

FAN LAW KEYS

Your calculator also has built-in formulas and keys that calculate Fan
Laws 1, 2 and 3, for air flow calculations. Each of these formulas
requires the entry of three variables in order to solve the fourth.

ÇR Fan Law 1 — Calculates the missing variable (e.g.,

“a-new” or “b-new” for CFM new or RPM new) for
Fan Law 1, given the three known variables into the
applicable Storage Registers (see below). See
page 75 for examples.

Çr Fan Law 2 — Calculates the missing variable (e.g.,

“a-new” or “b-new” for CFM new or SP new) for Fan
Law 2, given the three known variables into the
applicable Storage Registers (see below). See
page 76 for examples.

Çd Fan Law 3 — Calculates the missing variable (e.g.,

“a-new” or “b-new” for CFM new or BHP new) for
Fan Law 3, given the three known variables into the
applicable Storage Registers (see below). See

page 77 for examples.

Storage Registers Used For Fan Laws:

Ç4 Storage Register “a” — Enters “a-old” or current

“a” value.

Ç7 Storage Register “a-new” — Enters “a-new” or

new “a” value.

Ç5 Storage Register “b” — Enters “b-old” or current

“b” value.

Ç8 Storage Register “b-new” — Enters “b-new” or

new “b” value.

14 — ITI SHEET METAL/HVAC PRO

VELOCITY PRESSURE / FPM KEYS

Ç0 VP

ß©

FPM — Converts entry to Velocity (Feet per
Minute - FPM), Velocity Pressure, Metric Velocity
(MPS) and Metric Velocity Pressure (kPA).

Press Result

1 Calculates Velocity (FPM) – assumes

entry is Velocity Pressure

2 Calculates Velocity Pressure – assumes

entry is Velocity (FPM)

3 Calculates Metric Velocity (MPS) –

assumes entry is kPA

4 Calculates Metric Velocity Pressure

(kPA) – assumes entry is MPS

See page 46 for examples.

CIRCULAR / ARC FUNCTION KEYS

The Circle key helps you quickly solve Circular Area, Volume or Arc
problems.

C Circle — Displays and calculates the following val-

ues, given an entered Circle Diameter* or Radius:

• Diameter

• Circumference

• Circle Area

*To enter a Diameter (e.g., ten feet), press 10fC.To
enter a radius, see below.

Çp Segment Radius — Enters or calculates the Circle

Radius (e.g., 5fÇp). Used to calculate
Diameter, Circumference and Circle Area (see
above).

ÇC Arc Length or Degree of Arc — A multi-function

key that enters or calculates Arc Length or Degree
of Arc, and further solves for additional Circular/Arc
values, including Arched Rake-Walls (based on the
stored on-center), listed on next page.

(Cont’d)

USER’S GUIDE —15

(Cont’d)

If a Circle Diameter is entered into the C key and
Arc Degree (or Arc Length) entered into the Arc
function (ÇC), further presses of C will dis-
play and calculate the following:

Press

Result

1 Arc Length or Degree of Arc
2 Chord Length
3 Segment Area
4 Pie Slice Area
5 Segment Rise
6 Stored On-Center Spacing
7 Length of Arched Wall 1
8 Length of Arched Wall 2
9 Length of Arched Wall 3

(if applicable), etc.*

*Note: The calculator will calculate Arched Rake-Wall stud sizes
with consecutive presses of the C key until it reaches the last
stud.

R Run (Chord Length) — Used with r or Çpto

find the Chord Length or the Radius of a Circular
Segment. If the Segment Rise and Radius have
been entered, this key will display the Chord Length
of the Circular Segment.

r Rise — Used with R or Çpto find the Rise or

the Radius of a Circular Segment. If the Chord
Length and Radius have been entered, this key will
display the Segment Rise of the Circular Segment.

COLUMN / CONE KEY

The Column and Cone functions help you quickly estimate volume
and surface area of Columns or Cones.

Ç) Column and Cone — The first and second press of

) following Ç calculate the total volume and

surface area of a Column using the values stored in
C and r; the third and fourth consecutive press­es of ) calculate the total volume and surface area
of a Cone.

16 — ITI SHEET METAL/HVAC PRO

HIP/VALLEY and JACK RAFTER KEYS

Your calculator uses the y (rise), x (run), r (diagonal), θ (pitch), and
o.c. spacing values to calculate Regular (45°) and Irregular (non-45°)
Hip/Valley and Jack rafter lengths (excluding wood thickness, etc.).

When calculating Regular and Irregular Jack rafter lengths, you will
see the letters “JK” (Common Pitch side) or “IJ” (Irregular Pitch side)
and the corresponding Jack number to the left of your calculator dis­play. This will help you keep track of the descending sizes and which
side the corresponding rafter is based on.

H Hip/Valley Rafter — Finds the Regular (45°) or

Irregular (non-45°) Hip/Valley rafter length.

• Regular Hip/Valley Length: After Right
Triangle/Rafter values are entered or calculated
(e.g., Pitch, Rise, Run), pressing H will calculate
the length of the Regular Hip/Valley rafter.

• Irregular Hip/Valley Length: If an Irregular Pitch is
entered via ÇH(see next page), pressing
H will calculate the Irregular Hip/Valley rafter
length. (An Irregular or “non-standard” roof has two
different Pitches/Slopes.)

(Cont’d)

USER’S GUIDE —17

(Cont’d)

• Subsequent presses of the H key will also dis­play Plumb, Level, and Cheek cut angle values in
degrees.

ÇH Irregular Pitch — Enters the Irregular or Secondary

Pitch value used to calculate lengths of the Irregular
Hip/Valley and Jack rafters.

You may enter the Irregular Pitch as:

• a Dimension: 9iÇH

• an Angle: 30ÇH

• a Percentage: 75Ç+ÇH

Note: An entered Irregular Pitch can be recalled by pressing ®
ÇH.

j Jack Rafters — Finds the descending Jack rafter

sizes for Regular pitched roofs, based on the stored
on-center spacing and previously entered or calcu­lated Right Triangle/Rafter values (e.g., Pitch, Rise,
Run).

• The default On-Center spacing is 16 Inches. A new
On-Center spacing may be entered and permanent­ly stored by entering an Inch value prior to perform­ing the Jack Rafters function (e.g., 12i
j). The current On-Center spacing value can be
viewed by pressing ®j.

• Repeated presses of the j key will display all
the rafter sizes (on the regular pitch side) as well as
display the Plumb, Level, and Cheek cut angle val­ues. Additional presses will display the rafter sizes
on the Irregular Pitch side (if an Irregular Pitch was
entered; see above), or repeat the previously dis­played values.

Note: You may set your calculator to display the Jack rafter
lengths in either ascending or descending order (see Preference
Settings on page 107).

Note: You may program your calculator to “mate up” the Jack
rafters, rather than using the entered or default on center for both
sides (see Preference Settings on page 107).

18 — ITI SHEET METAL/HVAC PRO

Çj Irregular Side Jacks — Operates same as j,

but displays the rafter values from the irregular
pitched side first.

STAIR KEY

Your calculator easily calculates stair layout solutions. Given values
for r (Rise) and/or R (Run), your calculator will calculate Riser, Tread,
Stringer and Angle of Incline values simply by pressing the s key.

s A multi-function key that uses a stored “desired”

Riser height, stored “desired” Tread width, stored
Headroom and Floor Thickness, and entered r
(Rise) and/or R (Run) values to calculate and dis­play the following:

Press Result

1 Riser Height
2 Number of Risers
3 Riser Overage/Underage
4 Tread Width
5 Number of Treads
6 Tread Overage/Underage
7 Stairwell Opening
8 Stringer Length
9 Angle of Incline*
10 Run (entered or calculated)
11 Rise (entered or calculated)
12 Stored Riser Height
13 Stored Tread Width
14 Stored Headroom Height
15 Stored Floor Thickness

Note: Default values are 7-1/2 Inches for Desired Riser Height
and ten Inches for Desired Tread Width, ten Inches for Floor
Thickness and 6 Feet 8 Inches for Headroom.

Note: It is not possible for the calculator to include the Nose/
Overhang Measurement. Thus, you need to adjust for this meas­urement per local codes.

*Note: If the inclination angle exceeds the stored Rise and stored
Run ratio by 10%, the yield symbol (
steep incline.

will light, indicating a

)

USER’S GUIDE —19

Çs Store Desired Riser Height — Stores a value other

than the default desired stair Riser height of
7-1/2 Inches (e.g., 8iÇsstores an

eight-inch desired stair Riser height). To recall the
stored setting, press ®s.

Ç== Store Desired Tread Width — Stores a value other
== than the default desired stair Tread width of ten inch-

es. See page 107 Preference Settings to view how
to use the + and – key to increase or decrease
stored Tread width.

Ç=== Store Headroom Height — Stores a value other
== than the default desired Headroom Height of six

Feet eight Inches, for calculation of stairwell open­ing. See page 107 Preference Settings to view how
to use the + and – key to increase or decrease
stored Headroom height.

Ç=== Store Floor Thickness — Stores a value other than
=== the default desired Floor Thickness of ten Inches.

See page 107 Preference Settings to view how to
use the + and – key to increase or decrease
stored Floor Thickness.

20 — ITI SHEET METAL/HVAC PRO

GETTING STARTED

You may want to practice getting a feel for your calculator keys by
reading through the key definitions and learning how to enter basic
Feet-Inch-Fractions and Metric, how to store values in Memory, etc.,
before proceeding to the examples.

You may also want to glance at various formulas listed in the
Appendix, so you understand what mathematical calculations your
calculator is programmed to perform, or common formulas you can
refer to on the job. Also review specific default settings or
Preference Settings, listed in the Appendix.

ORDER OF OPERATIONS

Unlike other Calculated Industries’ calculators, which use the
Chaining Method of Operations, this calculator uses the Order of
Operation Method.

— Chaining Method (“as entered”): 10 +4x5=70

— Order of Operations: 10 + 4 x 5 = 30

The Order of Operations method of computing is based on the fol­lowing order of preference:

1) Expressions inside of parentheses

2) Single-variable functions that perform the calculation and
display the result immediately (Trig functions, Square,
Square Root, Cube, Cube Root, Log, Percent, Reciprocal,
Angle Conversions)

3) Exponential function

4) Multiplication and Division

5) Addition and Subtraction

6) Equals (completes all operations)

If you need to calculate using the Chaining Method, you can change
this in your calculator Preference Settings. See page 107 for instruc­tions.

USER’S GUIDE —21

USING PARENTHESES

Your calculator has Parentheses keys ( and ) for performing
mathematical operations. (In the Order of Operations method,
expressions inside of parentheses are performed first.)

The calculator offers four levels of parenthesis:

1) First parenthesis level opened – press ( for one Right-

Sided Parenthesis.

2) Second level opened – press ( a second time for two
Right-Sided Parentheses ((.

3) Third level opened –press( a third time for three Right­Sided Parentheses (((.

4) Fourth level opened – press ( a fourth time for four Right­Sided Parentheses ((((.

As you close each level of Parenthesis, the displayed number of
Parentheses in the upper left corner of the LCD is reduced by one,
and the results of expression are displayed.

22 — ITI SHEET METAL/HVAC PRO

SETTING FRACTIONAL RESOLUTION

Your calculator is set to display fractional answers in 16ths, and all
examples in this User Guide are, therefore, based on 1/16ths.
However, you may select the fractional resolution to be displayed in
other formats (e.g., 1/64ths, 1/32nds, etc.). Follow the two options
for selecting fractional resolution below.

Setting Fraction Resolution to Other Than 16ths —

Using the Preference Setting Mode

KEYSTROKE DISPLAY

1. Access Preference Settings:

Ç=(default setting = 1/16th of an Inch) FRAC 0-1/16 INCH

2. Access Next Fraction Sub-setting:

+ FRAC 0-1/32 INCH
+ FRAC 0-1/64 INCH
+ FRAC 0-1/2 INCH
+ FRAC 0-1/4 INCH
+ FRAC 0-1/8 INCH
+ (returns to 16ths) FRAC 0-1/16 INCH

3. To Permanently Set the Fraction Resolution You Have Selected
Above, Press o or Any Key to Exit:

o 0.

4. To Recall Your Selected Fraction Resolution:

®/ STD 0-1/16 INCH

USER’S GUIDE —23

Setting Fixed/Constant Fractional Resolution

You can also program your calculator so that the displayed fraction
will always show in the fractional resolution you have set (following
the above instructions). That is, instead of solving for the closest
fraction, it will always display the chosen fractional resolution. For
example, if you have chosen 1/64ths, 1/2 will be displayed as 32/64.

If you do not use this feature, Standard Fractional Resolution will be
displayed. In other words, in the above example, 1/2 will be dis­played as 1/2.

To change your calculator to Fixed (or Constant) Fractional Resolution:

KEYSTROKE DISPLAY

1. Access Preference Settings:

Ç= FRAC 0-1/16 INCH

2.

Press = 12 times to access Fixed/Constant Fractional Resolution setting:

= (twelfth press of = ) FRAC Std.

3. Change setting by pressing + :

+ FRAC COnSt
+ (returns to Standard) FRAC Std.

4. To permanently set the Fixed/Constant Fractional Resolution set-

ting, press o or any key to exit.

o 0.

5.

To recall your selected Fixed/Constant Fractional Resolution setting:

®/ (default settings) STD 0-1/16 INCH

24 — ITI SHEET METAL/HVAC PRO

ENTERING DIMENSIONS

Entering Linear Dimensions

When entering Feet-Inch-Fraction values, enter dimensions from
largest to smallest — e.g., Feet before Inches, Inches before
Fractions. Enter Fractions by entering the numerator (top), pressing
/ (Fraction bar key) and then the denominator (bottom).

Note: If a denominator is not entered, the fractional setting value is used.

Examples (press o after each one):

DIMENSION KEYSTROKES

5Feet1-1/2Inch 5f1i1/2

17.5 Meters 17•5m
32 Millimeters 32Çm

Entering Square/Cubic Dimensions

Your calculator lets you easily enter Square and Cubic values.
Simply press a dimensional unit key two times to label a number as
a Square value, or three times to label a Cubic value.

Note: If you pass the desired dimensional format, keep on pressing the dimensional
unit key until the desired result is displayed.

Enter Square and Cubic dimensions in the following order:

(1) Enter numerical value (e.g., 100).
(2) Press desired unit key (e.g., f) to label value as “linear.”

KEYSTROKE DISPLAY

oo 0.
100f 100

(3) Second consecutive press of unit key (e.g., f) labels value as
“Square.”

KEYSTROKE DISPLAY

oo 0.
100ff 100 SQ FEET

(4) Third consecutive press of unit key labels value as “Cubic.”

KEYSTROKE DISPLAY

oo 0.
100fff 100 CU FEET

Note: Feet-Inch format cannot be used to enter Square or Cubic values.

FEET

USER’S GUIDE —25

Examples of Square and Cubic Entry:

FEET

ff— Square Feet
(e.g., 5ffwill display 5.

SQ FEET).

fff— Cubic Feet
(e.g., 5fffwill display 5.

INCHES

CU FEET).

ii— Square Inches
(e.g., 5iiwill display 5. SQ INCH).

iii— Cubic Inches
(e.g., 5iiiwill display 5. CU INCH).

METERS

mm— Square Meters
(e.g., 5mmwill display 5. SQ M).

mmm— Cubic Meters
(e.g., 5mmmwill display 5. CU M).

MILLIMETERS

Çmm— Square Millimeters
(e.g., 5Çmmwill display 5. SQ MM).

Çmmm— Cubic Millimeters
(e.g., 5Çmmmwill display 5. CU MM).

26 — ITI SHEET METAL/HVAC PRO

CONVERSIONS (LINEAR, AREA, VOLUME)

Linear Conversions

Convert 14 Feet to other dimensions:

KEYSTROKE DISPLAY

oo 0.
14f 14 FEET
Çi 168 INCH
m* 4.267 M
Çm(mm) 4267.2 MM

*Note: When performing multiple conversions, you only have to press the Ç key
once (except when accessing secondary functions (Millimeters), e.g., Çm).

Converting Feet-Inch-Fractions to Decimal Feet

Convert 15 Feet 9-1/2 Inches to Decimal Feet. Then convert back to
Feet-Inch-Fractions.

KEYSTROKE DISPLAY

oo 0.
15f9i1/2

15 FEET 9-1/2 INCH

Çf 15.79167 FEET
f 15 FEET 9-1/2 INCH

Converting Decimal Feet to Feet-Inch-Fractions

Convert 17.32 Feet to Feet-Inch-Fractions.

KEYSTROKE DISPLAY

oo 0.
17•32f 17.32 FEET
Çf 17 FEET 3-13/16 INCH

Converting Fractional Inches to Decimal Inches

Convert 8-1/8 Inches to Decimal Inches. Then convert to Decimal
Feet.

KEYSTROKE DISPLAY

oo 0.
8i1/8 8-1/8 INCH
Çi 8.125 INCH
f 0.677083 FEET

USER’S GUIDE —27

Converting Decimal Inches to Fractional Inches

Convert 9.0625 Inches to Fractional Inches. Then convert to Decimal
Feet.

KEYSTROKE DISPLAY

oo 0.
9•0625i 9.0625

INCH

Çi 9-1/16 INCH
ff 0.755208 FEET

Square Conversions

Convert 14 Square Feet to other Square dimensions:

KEYSTROKE DISPLAY

oo 0.
14ffÇi 2016. SQ INCH
m 1.300643 SQ M
Çm(mm) 1300642.56* SQ MM

*For larger digit displays, the numerator section is utilized for decimal displays.

Cubic Conversions

Convert 14 Cubic Feet to other Cubic dimensions:

KEYSTROKE DISPLAY

oo 0.
14fffÇi 24192. CU INCH
m 0.396436 CU M

28 — ITI SHEET METAL/HVAC PRO

PERFORMING BASIC MATH WITH DIMENSIONS

Adding Dimensions

KEYSTROKE DISPLAY

Add 11 Inches to 2 Feet 1 Inch:

11i+2f1i= 3 FEET 0 INCH

Add 5 Feet 7-1/2 Inches to 18 Feet 8 Inches:

5f7i1/2+18f8i=

Subtracting Dimensions

KEYSTROKE DISPLAY

Subtract 3 Feet from 11 Feet 7-1/2 Inches:

11f7i1/2–3f= 8

Subtract 32 Inches from 81 Inches:

81i–32i= 49 INCH

Multiplying Dimensions

KEYSTROKE DISPLAY

Multiply 5 Feet 3 Inches by 11 Feet 6-1/2 Inches:

5f3ix11f6i1/2=

Multiply 2 Feet 7 Inches by 10:

2f7ix10= 25 FEET 10 INCH

24 FEET 3-1/2 INCH

FEET 7-1/2 INCH

60.59375 SQ FEET

Dividing Dimensions

KEYSTROKE DISPLAY

Divide 30 Feet 4 Inches by 7 Inches:

30f4i÷7i= 52.

Divide 20 Feet 3 Inches by 9:

20f3i÷9= 2 FEET 3 INCH

USER’S GUIDE —29