Engineer Architect Scales

8/20/2019 Engineer Architect Scales

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Using Engineer and Architect Scales

NOE: When PRINING this document, be sure the pull down

menu next to “Print Scaling” in the Print Dialog window is setto “None”. Tis will ensure the sample drawings will measureaccurately.

Introduction

Using and interpreting inormation rom engineer(civil) and architect scales is an important fire protectionengineering skill. Construction and fire protectionequipment drawings must be interpreted with a highdegree o accuracy.

Student Performance Objective

Given an architect or engineer scale and a set o scaleddrawings, you will be able to select the correct scale (tool)and interpret dimensions with 100 percent accuracy.

Enabling Objectives

1) You will be able to identiy the difference between

engineer (civil) and architect scales.2) Using a scale, you will be able to measure objects

shown on civil engineering plans and architecturalrenditions o buildings and structures.

3) You will be able to interpret the results o themeasurements.

Scales

Beore they are built or assembled, roads, water mains,

structures, and fire protection systems are designedin accordance with nationally recognized standards.Te design concept is transerred to a set o plans(drawings) that provide a two- or three-dimensionalrepresentation o the project.

Since

it would be impracticalto create ull-size drawings or theseobjects, they are reduced to a manageable size (scale)so they can be studied. A set o plans may include a variety o different scales, depending upon whaobjects are being rendered. Te selected scale normallyis ound in the title block in the lower right hand cornero the drawings, but may be ound anywhere on theplans. You may find more than one scale on a singlesheet when there are “details,” parts o the objects thatare enlarged or clearer explanation.

In order to interpret the size o what the renderingsrepresent, the plan reviewer must use a tool calleda “scale.” Te word “scale” is used synonymouslyto represent the tool and the size reduction in thedrawing. Te scale tool provides a quick method ormeasuring the object and interpreting its eventual sizewhen finished.

Selecting the Correct Tool

raditional scales are prism-shaped tools that looksimilar to the rulers you may have used in elementaryschool. Tere are two types o drafing scales used indesign and construction:



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1. Engineer, or civil, scales, such as 1˝ = 10´ or 1˝ = 50´,

are used or measuring roads, water mains, andtopographical eatures. Te distance relationshipsalso may be shown as 1:10 or 1:50.

2. Architect scales, such as 1/4˝ = 1´-0˝ (1/48 size) or1/8˝ = 1́ -0˝ (1/96 size), are used or structures andbuildings. Tey are used to measure interior andexterior dimensions such as rooms, walls, doors,windows, and fire protection system details.

Other scale tools include flat scales and rolling scales.

Rolling scales have the advantage o being able tomeasure travel distances easily, an important eaturewhen evaluating means o egress.

1. Look closely at the dimensions shown on the aceso the tools.

• Architect scales have numbers that runincrementally both rom lef to right and romright to lef . A whole number or raction to the

lef or right o the number line indicates thescale those numbers represent.

• Engineer scales have numbers that runincrementally rom lef to right . Te wholenumber to the lef o the number line indicatesthe scale those numbers represent.

2. Architect scales use ractions and have the ollowingdimensional relationships:

3/32 = 1 oot 1/4 = 1 oot 3/4 = 1 oot

3/16 = 1 oot 3/8 = 1 oot 1 inch = 1 oot

1/8 = 1 oot 1/2 = 1 oot 1½ inches = 1 oot

• Te scale marked “16” is a standard ruler.

• You must learn to read both rom lef to rightand right to lef. Note in the example below, thenumbers on the 1/8-inch scale increase romlef to right . Te numbers on the 1/4-inch scaleincrease rom right to lef .

• Note that the “0” point on an architect scaleis not at the extreme end o the measuringline. Te numbers “below” the “0” representractions o one oot.

1/8 1/4

0 4 8 12 92

46 44 42 2 0

3. Engineer scales have the ollowing dimensionarelationships:

1 inch = 10 eet 1 inch = 40 eet



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0 2 4 6 8 10

• When using the engineer scale, you mustmultiply the value you identiy by 10.

• Te small lines between the whole numbersrepresent individual eet, so a point that allstwo marks to the right o the whole number 4 isinterpreted as 42 eet.

Using the Tool and Interpreting the Results

You should never use your scale to draw lines. It shouldbe used only or measuring.



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1. Identiy the scale shown on the plans by the

architect, engineer or fire protection contractor(i.e., 1/8 = 1 oot; 1:40).

2. Select the object you wish to measure, and selectthe appropriate architect or engineer scale (tool).

3. Align your scale tool with the selected scale to veriy they match. During blueprint reproduction,the image size may be adjusted to fit the paper so itmay not represent precisely the scale the designerintended to use.

4. Correctly align the “0” with one end o the objectas a starting point, and identiy the object’s endpoint. Te corresponding number on the scale toolrepresents the object’s length when built.

Example No. 1:

Te drawings state that the scale is 1/8 inch equals1 oot. Using your architect scale, select the ace othe tool with the 1/8 mark in the upper lef-handcorner. Lay the “0” point at the extreme lef endo this line, and read the corresponding value at the

right end o the line.

You should see the value “32” on your scale. Givena 1/8-inch scale, this line represents a 32-oot longobject.

Example No. 2:

Using the same line, measure the distance using a1/4-inch to 1-oot scale. In this example, you will laythe “0” end o the tool on the right end o the line.

Te lef end o the line should correspond to the“16” on your scale. Tis line represents a 16-ootlong object even though the line on the paper is thesame length as the one above: that is the influenceo “scale.”

I the object’s end point does not align exactly with

a corresponding oot mark, slide the scale right orlef until the ractional mark aligns, then take yourreading. ranslate the raction into inches (e.g., the1/2 mark equals 6 inches, the 3/4 mark equals 9inches).

Example No. 3:

Using the same line, measure the distance using a3/8-inch to 1-oot scale. Lay the “0” at the lef endo the scale on the lef end o the line.

You will see that the right end o the line allsbetween 10 and 11 eet. Slide the scale to the rightuntil the 10 oot mark aligns with the right end othe line.

Now, look at the marks on the lef end o the line,lef o the “0.” Te lef end o the line correspondsto the ninth mark lef o the “0,” which in this caserepresents 9 inches. Tus, in a scale o 3/8 inch to 1oot, this line represents an object 10 eet, 9 inches

long.

Example No. 4:

Use the same line, but this time you are measuringa “water main” and the plans show a scale o 1 inchequals 20 eet. Use the engineer scale to measurethis water line.

Lay the engineer scale marked “20” on the lef end

o the line. Te right end o the line should alignwith the number “8”. Remember to multiply that value by 10 to get an answer o “80 eet.”

ry the activities on the next pages to test your newskills. Te answers are ound on the last page.



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1. Measure the height and width o this rectangle. Te scale is 1/4 inch equals 1 oot.

Height: eet Width: eet

2. Measure the exterior dimensions o this rectangle. Te scale is 1/8 inch equals one oot.

Height: eet Width: eet

3. In scale, how ar apart are these two rectangles?

55 eet



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4. Tis drawing represents the plan view o a bulk tank acility. Te scale is 1:60. What are the tank diameters in

eet?

Tank No. 1 Tank No. 2

Tank No. 3

Tank No. 6TankNo. 5Tank No. 4

ank No. 1 =_________eet

ank No. 2 =_________eet

ank No. 3 =_________eet

ank No. 4 =_________eet

ank No. 5 =_________eet

ank No. 6 =_________eet

5. Given the above inormation, how ar apart at their nearest edges are anks 1 and 6, measured in a straightline?

6. Tis drawing represents the floor plan o a small office. Given a scale o 3/32 = 1 oot, how long in eet is theexit access corridor?

Office

(Typical)

Rest

Room

Exit Access Corridor



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Scale versus Dimensions

While using a scale tool is an important skill, there are times when the fire inspector must rely on otherinormation.

When drawings are prepared with dimensions written on the plans, the written dimensions always take precedenceover scaled measurements.

During blueprint reproduction, the image size may be adjusted to fit the paper, so it may not represent precisely thescale the designer intended to use. I the image was adjusted just a small amount, its accuracy would be in doubtTereore, the dimensions written on the plans should be used.

Example

A fire sprinkler contractor submits drawings with the branch lines marked as ollows:

8´6˝

You apply your scale to veriy the dimensions, and discover the sprinklers are 10 eet apart based on your scaleHow do you reconcile the difference?

Te correct answer is 8 eet, 6 inches, because the written dimensions always take precedence over scaledmeasurements. In this example, you likely would obtain inaccurate scaled dimensions anywhere on thedrawings when using your scale tool.



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Activity answers

(Note: Your answers may be slightly different rom these due to margins o error among scale tools.)

1. Height = 5 eet, width = 21 eet, 6 inches

2. Height = 12 eet, width = 33 eet, 4 inches

3. Using the engineer scale tool, you must first establish which scale was selected. By rotating the scale tool untilyou align it with a known dimension (55 eet), you will see that the selected scale is 1 inch = 50 eet. Applyingthe scale tool to the outer edges o the rectangles reveals they are spaced 70 eet apart.

4. ank No. 1 = 105 eet ank No. 4 = 44 eet

ank No. 5 = 32 eet

ank No. 6 = 62 eet

ank No. 2 = 90 eet

ank No. 3 = 99 eet

5. 86 eet

6. 53 eet

Engineer Architect Scales

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