NATIONAL BUREAU OF STANDARDS REPORT

7331

PERFORMANCE TEST OF AN OWENS-CORNING

"DUST-STOP TYPE C" AIR FILTER

by

Carl W. Coblentz and Paul R. Achenbach

Report to

Public Buildings Service

General Services Administration

Washington 25, D. C.

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

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rim Ur r lii IftL UdC Urn
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent

with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; invention and' development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic

and applied research, development, engineering, instrumentation, testing, evaluation, calibration services,

and various consultation and information services. Research projects are also performed for other government

agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau’s

unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover.

Publ ications

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in the journals of professional and scientific societies. The Bureau itself publishes three periodicals avail- able from the Government Printing Office: The Journal of Research, published in four separate sections,

presents complete scientific and technical papers; the Technical News Bulletin presents summary and pre- liminary reports on work in progress; and Basic Radio Propagation Predictions provides data for determining

the best frequencies to use for radio communications throughout the world. There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series, Handbooks, Miscellaneous Publications,

and Technical Notes. A complete listing of the Bureau’s publications can be found in National Bureau of Standards Circular

460, Publications of the National Bureau of Standards, 1901 to June 1947 ($1.25), and the Supplement to National Bureau of Standards Circular 460, July 1947 to June 1957 ($1.50), and Miscellaneous Publication 240,

July 1957 to June 1960 (Includes Titles of Papers Published in Outside Journals 1950 to 1959) ($2 .25); avail- able from the Superintendent of Documents, Government Printing Office, Washington 25, D. C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

1003-30-10630 August 30, 1961

NBS REPORT

7331

PERFORMANCE TEST OF AN OWENS-CORNING

’'DUST-STOP TYPE C” AIR FILTER

by

C. W. Coblentz and P. R. Achenbach

Mechanical Systems Section

Building Research Division

to

Public Buildings Service

General Services Administration

Washington 25., D. C.

IMPORTANT NOTICE

NATIONAL BUREAU OF STAt

Intended for use within the Gr

to additional evaluation and rev listing of this Report, either In the Office of tho Director, Nath

however, by the Government af te reproduce additional copies

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

sgress accounting documents

lally published It Is subjected

^production, or opcn-lltcraturc

>n Is obtained In writing from

uch permission Is not needed,

repared If that agency wishes

U S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

FOR OFFICIAL USE ONLY

PERFORMANCE TEST OF AN OWENS-CORNING

"DUST-STOP TYPE C" AIR FILTER

by

C. W. Coblentz and P. R. Achenbach 1.

INTRODUCTION

At the request of the Public Buildings Service, General

Services Administ ration, the performance characteristics of

two specimens of a new type "C" throw-away type "Dust-Stop"

air filter were determined. The scope of this examination

included the determination of the arrestance of Cottrell

precipitate in the laboratory air, the pressure drop, and

the dust-holding capacity when the filters were operated at

350 ft/min face velocity.

2.

DESCRIPTION OF TEST SPECIMENS

The filters were manufactured and supplied for test

purposes by the Owens-Corning Fiberglas Corporation of

Toledo, Ohio. Two specimens were arbitrarily selected from

a factory-sealed carton containing six filters of the same

kind.

The nominal 20x20x1 inch filters actually measured

19 1/2 x 19 1/2 x 15/16 inches with a net face area of

17 7/8 inches square, i.e. 2.22 square feet. The filter

media consisted of a mat of bonded glass fibers. According

to the manufacturer’s information, hexachlorophene had been

added to the adhesive to provide a means for absorbing odors.

The filter media was supported on both faces by perforated

sheets of thin metal; the perforations consisted of 1 1/2

inch diameter cut-outs with approximately 1/32 inch material

left between the holes. The downstream face was further

reinforced by a V-shaped brace, the ends of which were held

in the channel-shaped cardboard frame. The weights of the

two specimens were 392 grams and 375 grams (13 7/8 and 13 1/4

ounces), respectively.

3.

TEST METHOD AND PROCEDURE

The performance of the test specimens was determined at

a face velocity of 350 ft/min, i.e. an air flow rate of j80

cfm. The arrestance measurements were conducted in accordance

with the "NBS Dust Spot Method, " as described in a paper by
- 2 -

R. S. Dill entitled "A Test Method for Air Filters" (ASHVE

Transactions, Vol. 44, p. 379 , 1938).

The filter under test was supported in a wooden frame

that fitted the test apparatus and was carefully sealed to

prevent any by-pass of air or inward leakage into the test

apparatus,, except through the measuring orifice. The desired rate of air flow through the filter was established,

and samples of air were drawn from the center points of the

test duct 2 feet upstream and 8 feet downstream of the test

specimen at equal rates, and passed through known areas of

Whatman No. 4l filter paper. The arrestance determinations

were made with laboratory air, into which Cottrell precipitate was injected and diffused at a ratio of 1 gram per

1,000 cubic feet of air.

The two sampling papers used in every test were selected

to have the same light transmission when clean. The light

transmission of the same portion of each paper was measured

before and after the tests. In order to obtain similar increases of opacity with both sampling papers, different-size

areas were used upstream and downstream of the filter. The

arrestance, A (in percent), was then calculated by the

following formula:

A (1 —Sd ad.x —

)

s v

aid

x 100

where Sp and Su are the downstream and upstream areas and

AD and AU the changes of the opacity of the exposed areas

of the downstream and upstream sampling papers, respectively.

Whereas the arrestance determinations were made with

Cottrell precipitate only, cotton lint was added during the

loading process in a ratio of 4 parts to every 96 parts by

weight of Cottrell precipitate, including that amount used

for arrestance measurements. The Cottrell precipitate had

been previously sifted through a 100-mesh screen and the

lint was prepared by grinding No. 7 cotton linters through

a Wiley mill with a 4 millimeter screen.

Arrestance determinations were made at tiae beginning

and at the end of the loading period of each specimen and

at several intermediate load conditions. The pressure drop

across the filter under test was recorded after each increment of 20 grams of dust had been introduced into the

test duct. The test was terminated after the pressure drop

reached 0.5 in. W.G.
-3-

4. TEST RESULTS

The results observed during tests of the two specimens

are presented in Table 1, which shows the dust load, the

pressure drop, and the arrestance values.

Table 1

Performance of Owens-Corning "Dust-Stop” Air Filter

1-inch thick, 350 ft/min Face Velocity

Pressure Drop

in. W. G.

Dust Load

g/sq ft

Arrestance

%

Specimen No. 1

0.095

0.190

0.265

0.353

0.491

0.5H

4 64*

54 70*

106 73*

157 77*

225 75*

231

Specimen No, 2

0.095

0.216

0.264

0.314

0.378

0.447

0.501

4 69

60 74

85 76

ill 81

135 82

160 82

177 81

* Indicates average of two arrestance determinations.

The "dust load" shown In this table is the weight of

dust received per 1 square foot of net filter area. It Is

the amount of Cottrell precipitate and lint introduced into

the test apparatus divided by the net face area of the filter, and diminished by the percentage of dust fall-out upstream of the filter. This dust fall-out was determined at

the conclusion of the test of each specimen by weighing the

amount of dust that was swept out of the upstream part of

the test duct, and calculating the percentage of fell-out to

the total amount of dust introduced. The "dust-holding

capacity" shown in Table 2, the Summary of Test Results,

presents the dust load at the final pressure drop of 0.50 In.

W.G. across the filter.
-4-

Table 2

Summary of Test Results

Pressure Drop,

Specimen No. 1 Specimen No. 2 Average

Clean, in. W.G.

Arrestance,

0.093 0.090 0.092

Clean, %

Arrestance,

64 69 67

Loaded, %

Arrestance, Average

75 81 78

during loading, %

Dust-Holding

73 77 75

Capacity, g/sq ft 227 175 201

There was a considerable difference in the performance

of the two test specimens. The difference may have been

caused by different density of the filter media or unlike

amounts of adhesive applied to the media. Specimen No. 1,

which was 1J grams (about 5$) heavier than the second specimen,

showed an initial pressure drop of 0.093 in. W.G. against

0.090 in. W.G. of the lighter filter. The initial arrestance

of the two specimens differed considerably; it was 64 percent

and 69 percent for specimens 1 and 2, respectively. Corresponding to the lower arrestance,, the dust-holding capacity

of the first specimen was about 130 percent of that for the

second one.

Figure 1 is a graphical representation of the values

shown in Table 1 with smooth curves approximating the lines

of the least mean square distances from the respective points

of observation. The curves indicate a dust-holding capacity

of 227 grams for specimen No. 1 and of 175 guams for specimen

No. 2 at the limiting value of 0.50 in. W.G. Both specimens

revealed an increase in arrestance as the filters were loaded

up to approximately 0.4 in. W„G. Thereafter, the arrestance

values decreased,, which may indicate that some dust was being

pulled off the media. The average arrestance of the two

specimens during the loading period., up to a maximum pressure

drop of 0.50 in. W.G.., was approximately 73 and 77 percent,,

respectively. Table 2 shows a summary of the test results

of each specimen and the averages for the two specimens.

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u. s. department of commerce

Luther H. Hodges, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In general, each section carries out specialized research, development, and engineering in the field indicated by

its title. A brief description of the activities, and of the resultant publications, appears on the inside of the

front cover.

WASHINGTON, D.G.

Electricity. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements.

Dielectrics. Metrology. Photometry and Colorimetry. Refractometry. Photographic Research. Length. Engineering Metrology.

Mass and Scale. Volumetry and Densimetry.

Heat. Temperature Physics. Heat Measurements. Cryogenic 'Physics. Equation of State. Statistical Physics.

Radiation Physics. X-ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological Equipment.

Nucleonic Instrumentation. Neutron Physics.

Analytical and Inorganic Chemistry. Pure Substances. Spectrochemistry. Solution Chemistry. Standard Refer- ence Materials. Applied Analytical Research.

Mechanics. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Rheology. Combustion

Controls. Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Physics. Electrolysis and Metal Deposition.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Crystal Growth. Physical

Properties. Constitution and Microstructure. Building Research. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials. Codes and Safety Standards. Heat Transfer. Inorganic Building Materials. Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics. Operations Research. Bata Processing Systems. Components and Techniques. Digital Circuitry. Digital Systems. Analog Systems.

Applications Engineering.

Atomic Physics. Spectroscopy. Infrared Spectroscopy. Solid State Physics; Electron Physics. Atomic Physics.

Instrumentation. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical Instru- ments. Basic Instrumentation. Physical Chemistry. Thermochemistry. Surface Chemistry. Organic Chemistry. Molecular Spectroscopy. Molecular Kinetics. Mass Spectrometry.

Office of Weights and Measures. BOULDER, COLO.

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Cryogenic Technical Services. Ionosphere Research and Propagation. Low Frequency and Very Low Frequency Research. Ionosphere Research.

Prediction Services. Sun-Earth Relationships. Field Engineering. Radio Warning Services.

Radio Propagation Engineering. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements.

Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

Radio Standards. High Frequency Electrical Standards. Radio Broadcast Service. Radio and Microwave Materials. Atomic Frequency ana Time Interval Standards. Electronic Calibration Center. Millimeter-Wave Research.

Microwave Circuit Standards. Radio Systems. High Frequency and Very High Frequency Research. Modulation Research. Antenna Research.

Navigation Systems.

Upper Atmosphere and Space Physics. Upper Atmosphere and Plasma Physics. Ionosphere and Exosphere

Scatter. Airglow and Aurora. Ionospheric Radio Astronomy.
11)

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