NATIONAL BUREAU OF STANDARDS REPORT

8522

PERFORMANCE CHARACTERISTICS OF A "ULOK",

MODEL 87 BT, DISPOSABLE, VISCOUS TYPE,

SYNTHETIC FIBER AIR FILTER

manufactured by

Linde Division, Union Carbide Corporation

New York, New York

by

Joseph C. Davis and Paul R. Achenbach

Report to

General Services Administration

Public Building Service

Wash ing t on , D . C

.

11. S. DEPARTMENT OF COMMERCE

NATIONAL BOREAO OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards is a principal focal point in the Federal Government for assuring

maximum application of the physical and engineering sciences to the advancement of technology in industry and commerce. Its responsibilities include development and maintenance of the national stand- ards of measurement, and the provisions of means for making measurements consistent with those standards; determination of physical constants and properties of materials; development of methods

for testing materials, mechanisms, and structures, and making such tests as may be necessary, particularly for government agencies; cooperation in the establishment of standard practices for incorporation in codes and specifications; advisory service to government agencies on scientific and technical problems; invention and development of devices to serve special needs of the Government; assistance

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lb-ting of its four Institutes and their organizational units. Institute for Basic Standards. Electricity. Metrology. Heat. Radiation Physics. Mechanics. Applied Mathematics. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radio Standards Laboratory: Radio Standards Physics; Radio Standards Engineering.** Office of Standard Ref- erence Data. Institute for Materials Research. Analytical Chemistry. Polymers. Metallurgy. Inorganic Materials. Reactor Radiations. Cryogenics.** Office of Standard Reference Materials. Central Radio Propagation Laboratory.** Ionosphere Research and Propagation. Troposphere

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* NBS Group, Joint Institute for Laboratory Astrophysics at the University of Colorado. ** Located at Boulder, Colorado.
NATIONAL BUREAU OF STAMDAI^DS ^EPGS<¥

ms PROJECT

421.03-30-4210630 August 6, 1964

mS REPORT

8522

PERFORMANCE CHARACTERISTICS OF A "ULOK",

MODEL 87 BT, DISPOSABLE, VISCOUS TYPE,

SYNTHETIC FIBER AIR FILTER

manufactured by

Linde Division, Union Carbide Corporation

New York, New York

Joseph C. Davis and Paul R. Achenbach

Mechanical Systems Section

Building Research Division

to

General Services Administration

Public Buildings Service

Washington, D. C.

by

IMPORTANT NOTICE NATIONAL BUREAU OF STAN

for use within the Government. Be and review. For this reason, the pi whole or in part, is not authorize! Bureau of Standards, Washington I the Report has been specifically pre

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015.

accounting documents intended

rjected to additional evaluation

;ting of this Report, either in

Iffice of the Director, National

8 Government agency for which

es for its own use.

U. S. DEPARTMENT OF COMMERCE

Performance Characteristics of a "Ulok",

Model 87 BT, Disposable, Viscous Type,

Synthetic Fiber Air Filter

manufactured by

Linde Division

Union Carbide Corporation

New York, N. Y.

by

Joseph C. Davis and Paul R. Achenbach

1 . INTRODUCTION

At the request of the Public Buildings Service, the performance characteristics of a "Ulok" Model 87 BT, disposabl

synthetic fiber filter manufactured by the Union Carbide

Corporation (Linde Division), New York, New York were

determined. The filter was a viscous type and was treated

with an air filter oil. The scope of the investigations

included the determination of the arrestance of the particulate matter of the laboratory air by the filter and

the pressure drop of the filter at the rated air-flow rate

of 9-40 cfm as the dust load was gradually increased from

zero to a final value corresponding to a pressure drop of

0.5' in . W.G.

2. DESCRIPTION OF TEST SPECIMEN

The filter was manufactured and supplied for test purposes

by the Union Carbide Corporation (Linde Division) New York,

New York. The outside dimensions of the filter unit were

20 3/4-'' x 20 3 04" x 2" deep. The filter media extended

1/2 inch beyond the edge of a metal supporting ring The

filter media area was approximately 3 ft^ and consisted

of an oil treated batt of Dynel Modacrylic* fiber, a synthetic material made from natural gas. .The media was

attached to a stiff 1/4-inch mesh resinyforcing scrim and

fastened to the metal supporting ring. The cross sectional

area of the Dynel fibers was irregular because of pertuberance on their surfaces. The diameter of the fibers was

approximately 5 microns; their average length was about

1 1/2-inches. The net face dimensions after installation

in the test apparatus was 19” by 19” equivalent to 2.51 ft2

* The name "Dynel Modacrylic" is a trade name.
;

ib;f- 'XV

'
At an air flow rate of 9^0 cfm, the net face velocity was

370 ft/mi n. the weight of the clean filter was about

323 grams or 11.4 oz.

3. TEST METHOD AND PROCEDURE

The filter was tested at the air flow rate of 940 cfm. The

arrestance determinations were made with the NBS Dust Spot

Method described in a paper by R. S. Dill entitled, "A

Test Method for Air Filters", (ASHVE Transactions, Vol. 44,

p. 379, 1938). The filter under test was installed in the

test apparatus and carefully sealed to prevent any bypass or inward flow of air into the test apparatus, except

through the measuring orifice. After establishing the

correct air flow rate through the filter, samples of air

were drawn from the center points of the test duct 2 feet

upstream and 8 feet downstream of the test specimen. Each

sample of air was passed through Whatman No. 41 filter

paper. The arrestance determinations were made with the

particulate matter in the laboratory air as the aerosol.

The filter was loaded with a mixture of Cottrell precipitate

and lint injected into the air stream at a ratio of 1 gram

per 1,000 cu. ft. of air.

The light transmission of the sampling papers was measured

on the same area of each paper before and after the test,

and the two sampling papers used for any one arrestance

determination were selected to have the same light transmission when clean.

For determining the arrestance of the particulate matter

in the laboratory air equal sampling areas were used in the

upstream and downstream filter papers. A similar increase

of the opacity of the two sampling papers was obtained by

passing the sampling air through the upstream paper only

part of the time while operating the downstream sampler

continuously. This time proportioning was accomplished by

the use of one solenoid valve in the upstream sampling

line and another in a line by-passing the sampler. The

solenoid valves were operated by an electric timer and

a relay so that one was open while the other one was closed

during any desired percentage of a 5-minute timer cycle,

reversing the position of the two valves during the remainder

of the cycle. The arrestance A, (in percent) was then

determined with the formula:

A = 100 T x AD

AU

- 2

-
.

. ", v;:

.
Where T Is the percentage of time during which air was

drawn through the upstream sampler, AU and AD are the

observed changes in the opacity of the upstream and

downstream sampling papers, respectively.

Arrestance determinations were made at the beginning and

at the end of the test and at several intermediate loading conditions as indicated in Table 1. The loading was

done incrementally, each increment consisting of 96 parts

Cottrell precipitate and 4 parts cotton linters, by weight.

The Cottrell precipitate had previously been 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.

The pressure drop across the filter under test was recorded at the beginning of the test, after each arrestance determination, and after each increment of Cottrell

precipitate and lint that was introduced into the test

duct. The test was terminated when the pressure drop

across the filter reached 0.5 in. W.G.

4 . TEST RESULTS

The test results obtained on the air filter specimens at

the air flow rate of 9^0 cfm or 370 fpm net face velocity

are summarized in Table 1.

TABLE 1

Performance of a Union Carbide Corporation "Ulok"

Disposable Air Filter 87 BT at a Face Velocity of 370 fpm

Cumulative Load

ittrell

:cipitate Lint Total

Arrestance of

Atmospheric

Aerosol

Pressure

Drop

Grams Grams Grams Percent In. W.G.

0 0 0 57.5 0.160

60 2.5 62.5 67.4 0.204

160 6 .6 • 166.6 74.8 0.280

260 10.8 270.8 80.9 0.350

360 14.9 374.9 81.4 0.432

460 19.1 479.1 80.2 0.520

- 3

-

It will be noted that pressure drop increased from 0.160

in. W.G. with a clean filter to 0.520 after a dust load

of 479 grams had been reached for the filter. The increase in pressure drop was almost proportional to the

dust load.

The arrestance of the dust in the atmospheric air increased

from 57*5 percent to 80.2 percent during the loading period

and averaged approximately 75-5 percent. The dust load

of Cottrell precipitate and lint corresponding to a pressure

drop of 0.50 in. W.G. was l80 grams/sq ft. of net face

area

.

The values show in Table 1 are graphically presented in

Figure 1. In this figure the arrestance of the particulate matter in the laboratory air and the pressure drop

are both plotted against the dust load.

- 4-

ISC0MM-KDS-DC
i
Pressure

Drop,

In.

W.G.

Arrestance,

percen

UNION CARBIDE (LINDE DIVISION)

"ULOK" MODEL 87 BT

DUST LOAD, Grams Fig. 1


i-

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