Learning Objectives. History of Vacuum Testing for Precast. Vacuum Testing. Terminology and purpose

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Vacuum Testing: It Just Sucks!

Presented by: Darryl Cloud Concrete Sealants, Inc.

Learning Objectives

In this course, you will learn: Vacuum Testing Terminology Vacuum Testing for Watertightness Vacuum Testing Equipment Tips, Tricks, and FAQ’s

History of Vacuum

Testing for Precast

Manufacturers of products depend on a number of quality control methods to ensure performance. One method available to the manufacturers of concrete products is vacuum testing. Vacuum testing is an easy and quick method of offering a high degree of reasonableness to the quality,

watertighness, and structural integrity to a host of products of varying geometrical configurations.

Not that long ago……

Effective August 1,1960 Deduct $15.00 if Ordered without bottom

Vacuum Testing

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Terminology

Definition of a vacuum:

According to the definition of the American Vacuum Society (1958) the term "vacuum" refers to a given space filled with gas at pressures below atmospheric.

In other words, a vacuum is the state of a gas

where the density of the particles is lower than

atmospheric pressure at the earth's surface.

Terminology

Inches of Mercury (in/Hg)

◦This is a unit of measure for pressure; it is the measure used by most barometers to measure atmospheric pressure

Negative Pressure

◦A pressure that is less than atmospheric, also referred to as a vacuum

Watertight

◦Construction such that water cannot pass through

except under significant pressure

Low Pressure “System”

1000 = 1 bar = 29.53” Hg

Vacuum Conversion

So Why

Vacuum

Test?

To eliminate:

Structures:

Vacuum testing is performed on: Septic Tanks

Manholes Pipe

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Purpose:

Because it improves the seal!

Before Vacuum After Vacuum

Vacuum Force

!

Purpose

ASTM Specification References

C 1214

◦Concrete Pipe Sewer lines (Field) C 1227, Section 9

◦Proving water tightness in septic tanks (Plant) C 1244

◦Concrete Sewer Manholes (Field)

C 1618

◦Concrete Sanitary Sewer Pipe (Plant)

Performance Test Methods

“Test procedures should be clearly defined prior to tank fabrication and installation. . . Consideration should be given to whether tests will be conducted in the plant or on-site (prior to or after backfilling).

ASTM C-1227: Vacuum Testing

Section 9.2.1. Vacuum Testing

Seal the empty tank and apply a vacuum to 4 inches (100MM) of

NPCA Best Practice Manual: Vacuum Testing Introduce a vacuum of 4 inches of mercury. Hold this pressure for five minutes. The tank must have no loss of pressure during the duration of the

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Vacuum Testing

Verifying Watertightness

in wastewater tanks

Septic tanks can be tested for water tightness using:

◦The water method

◦Negative pressure / vacuum method ◦WATERTEST vs. VACUUM TEST

Alternative Materials

Orenco literature states that tanks should always be water tested…

“Note: Vacuum testing is not acceptable, as it will not adequately test the flange joint and will not easily reveal very small leaks or leaks created by capillary action.” (Orenco assembly instructions NIN-TNK-4)

This is rhetoric! Let see why.

Watertight Testing – Water

Water Test per ASTM C 1227

◦Fill tank to the invert of the outlet

◦Let stand for 24 hours

◦Refill the tank

◦Tank passes if water level does not drop within 1

hour

Local Code Requirement

◦Fill the tank completely into the riser.

Water Column

2.17 psi @ 5' 4.35 psi @ 10' 6.52 psi @ 15' 8.7 psi @ 20' 10.87 psi @ 25' 13 psi @ 30' STAND PIPE

The force of water is a linear relationship to the height of the column. The force increases by 0.433 psi per foot.

Hydrostatic Cautions

1’ of water into the riser

◦creates 62 lb/ft2 _{of “lift”}

◦this will displace a top seal lid Use additional weight when necessary Don’t do it if you don’t have to!

A vacuum pulls the same at all heights

Vacuum Force

~30” Hg

Vacuum Force

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Vacuum Testing

◦Draw a vacuum on the tank of 4”+ Hg ◦Allow tank to settle

◦Return vacuum to 4” Hg ◦Shut valve and hold the vacuum ◦Tank is watertight if there is no loss of

vacuum after 5 minutes

Watertight Testing: In Field

Vacuum Testing

Verifying Watertightness

in manholes / pipe

Watertight Testing – In Plant

Manholes and Pipe can be tested for water tightness in the plant with automated equipment.

Watertight Testing – In Field

Manholes and Pipe can be tested for water tightness in the field using a vacuum pump or venturi.

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Minimum Test Times C1244-05a

Diameter (in) Depth 30 33 36 42 48 54 60 66 72 Time (s) 8’ 11 12 14 17 20 23 26 29 33 10’ 14 15 18 21 25 29 33 36 41 12’ 17 18 21 25 30 35 39 43 49 14’ 20 21 25 30 35 41 46 51 57 16’ 22 24 39 34 40 46 52 58 67 18’ 25 27 32 38 45 52 59 65 73 20’ 28 30 35 42 50 53 65 72 81 22’ 31 33 39 46 55 64 72 79 89 24’ 33 36 42 51 59 64 78 87 97 26’ 36 39 46 55 64 75 105 94 28’ 39 42 49 59 69 81 113 101 30’ 42 45 53 65 74 87 98 108 121

Caution!!!!

The negative internal

pressure may cause the

casting to implode.

Alternative Materials

This imploded at 11.5” of Hg (800 lb/ft2₎ Orenco brags about this!!!

In there literature, they state that this is substantially higher than the “worst-case load”

http://www.waterandwastewater.com/videos/view_video.php?viewkey =094e0b5cb1b01d712f70

Vacuum Testing

Equipment

Vacuum Test Equipment

Cherne

Vacuum Test Equipment

Plug-It

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Vacuum Testing Equipment

Home made

Vacuum Testing Equipment

Alternatives

Vacuum Testing

Tips and tricks

Tips and Tricks

1. Use the rubber gasket as supplied

2. Us a small diameter of butyl sealant

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Tips and Tricks

1. Duct tape…yea, it can be used for everything!

2. External Joint Warp

3. Expansion pipe plugs

Tips and Tricks

1. Listen…shhhh! You’ll hear the hissing. 2. Use a power audio detection device. 3. Use water / soapy water

Tips and Tricks

1. Cement slurry

2. Caulking

3. Epoxy sealers

4. Butyl sealant / butyl wrap