'^2/,

NATIONAL BUREAU OF STANDARDS REPORT

8571

PERFORMANCE TEST OF THE "KLEEN-AIR" GLASS FIBER

AUTOMATIC RENEWABLE FILTER MEDIA

manufactured by

the B &. M Filter Sales & Service, Inc. of Houston

Texas

by

Joseph C. Davis and Paul R. Achenbach

Report to

General Services Administration

Public Buildings Service

Washington 25, D.C.

11. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU 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

to industry, business, and consumers in the development and acceptance of commercial standards and

simplified trade practice recommendations; administration of programs in cooperation with United

States business groups and standards organizations for the development of international standards of

practice; and maintenance of a clearinghouse for the collection and dissemination of scientific, technical, and engineering information. The scope of the Bureau’s activities is suggested in the following

listing of its four Institutes and their organizational units. Institute for Basie 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

and Space Telecommunications. Radio Systems. Upper Atmosphere and Space Physics.

Institute for Applied Technology. Textiles and Apparel Technology Center. Building Research.

Industrial Equipment. Information Technology. Performance Test Development. Instrumentation.

Transport Systems. Office of Technical Services. Office of Weights and Measures. Office of Engineering Standards. Office of Industrial Services.

* NBS Group, Joint Institute for Laboratory Astrophysics at the University of Colorado. ** Located at Boulder, Colorado.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

421.03-30-42106030 November 2, 1964 8571

PERFORMANCE TEST OF THE "KLEEN-AIR" GLASS FIBER

AUTOMATIC RENEWABLE FILTER MEDIA

manufactured by

the B & M Filter Sales and Service, Inc.

of Houston, Texas

by

Joseph C. Davis and Paul R. Achenbach

to

General Services Administration

Public Buildings Service

Washington 25, D.C.

IMPORTANT NOTICE NATIONAL BUREAU OF I for use within the Governmen

and review. For this reason, whole or in part, is not autl Bureau of Standards, Washir

the Report has been specifica

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

jress accounting documents intended

is subjected to additional evaluation

ire listing of this Report, either in the Office of the Director, National by the Government agency for which

I copies for its own use.

II. $. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

PERFORMANCE TEST OF THE "KLEEN-AIR" GLASS FIBER AUTOMATIC

RENEWABLE FILTER MEDIA

manufactured by

the B & M Filter Sales and Service, Inc. of Houston,

Texas

1 . Introduction

At the request of the Public Buildings Service, General Services

Administration, the performance characteristics of the '*Kleen-Air"

glass fiber roll-type filter media, manufactured by the B & M Filter

Sales and Service, Inc. of Houston, Texas, were determined. The scope

of the investigations included the determination of the arrestance of

Cottrell precipitate diffused into the laboratory air, and the dustholding capacity when the face velocity was maintained at 500 ft/min

and while the media was intermittently advanced with a maximum setting

for the pressure drop across the media of 0.5 in. W.G. Three different rolls of the media, each having been processed with a different

amount of tricresy Iphosphate adhesive were investigated. A complete

test was performed only on roll No. 2.

2 . Description of Test Specimen

Each roll of the media was manufactured and supplied for test

purposes by the B & M Filter Sales and Service, Inc. of Houston,

Texas. The media was 32 inches wide and 2 in. thick, and was blue

in color. It had a 4x4 mesh scrim backing on the downstream side of

the media which, according to the manufacturer, was fire-retardant

and mildew-proof. The purpose of the scrim backing was to provide

support for the media during operation, in order to reduce deflection

and tearing of the media and possible breakage of the glass fibers.

The media was composed of spun glass fibers bonded with an organic

bonding agent. According to the manufacturer, each roll was processed with a different amount of adhesive. The amount of adhesive

on the three rolls as claimed by the manufacturer and as measured

by the National Bureau of Standards is summarized in Table 1.

Table 1

Roll No. 1 Roll No. 2 Roll No. 3

Unit Weight

of T.C.P. added

during man 1 f 'ng

8

11

16

Unit Weight

As Determined

in the NBS Lab.

g/ft 2

5

5 11

- 1-
The disparity between the two columns of unit weights cannot be

exactly accounted for. It is probable that most of it was caused by

losses during shipment when some of the adhesive drained into a polyethylene bag covering the roll, by drainage due to gravity when the

roll was under test and by handling during the cutting of the specimen to be analyzed. In the NBS analysis, determinations were made

using two adjacent specimens, each having an area of 2x6 in. A Soxlett Extractor was used with absolute alcohol as the solvent. The

unit weight of adhesive application was probably determined in the

factory by measurement of the total amount of adhesive sprayed on a full roll. Thus the application may not be entirely uniform and small

specimens may not be representative of the average.

Infrared analyses showed that the adhesive on all three rolls was tricresylphosphate (T.C.P.). Microscopic examination of the

fibers indicated that the fibers in the main body were between 2 and

6.5 microns in diameter. The length of these fibers ranged from about

3 to 10 inches. The approximate unit weight of the mat, including

scrim, was about 38 gram/ft2„

3 . Test Method and Procedure

The media on each roll was tested at a net face velocity of

500 ft/min. The arrestance determinations were made using the "NBS

Dust Spot Method for Air Filters" (ASHVE Transactions, Vol. 44, p. 379,

1938). For the test, the roll of media was installed in a roll-filter

frame constructed to fit the NBS test apparatus. This apparatus provided an airtight enclosure and adapters to fit the upstream and downstream sections of the test duct. This roll-filter frame has been

used previously for testing various media of this type.

The frame had two openings, 2 ft x 2 ft, one upstream and the

other downstream from the filter. The roll of filter media was placed

at the top of the frame on a spool and arranged so the media passed

immediately behind the downstream opening as it unrolled. The loaded

media was rolled up on a similar spool at the bottom of the frame.

The bottom spool was driven by a motor actuated manually when the

pressure drop across the media reached 0.5 in. W. G. Nine vertical

bars in the downstream opening served to prevent appreciable deflection of the media under the influence of the air pressure difference.

The edges of the media were enclosed in metal groove- type tracks to

restrict by-pass of air between the media and frame.

The frame and media were installed in the dust spot test apparatus and carefully sealed to prevent any by-pass of air or inward flow

into the test apparatus, except through the measuring orifice. After

establishing the correct air flow rate through the filter, samples of

- 2-
air were drawn from the center points of the test duct two feet upstream and eight feet downstream of the test specimen at equal rates

and passed through known area of Whatman No. 41 filter paper. The

arrestance determinations were made with Cottrell precipitate injected into the air stream with a ratio of one gram of dust per 1,000

cu ft of air.

The light transmission of the sampling papers was measured before and after the test on the same area of each paper, 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 filter, different size areas of sampling paper were exposed upstream and downstream of the

filter in order to obtain a similar increase of opacity on the two

sampling papers. The arrestance was calculated by the formula:

S D AD

A = ^x x 100

where the symbols Sy and Sjj are the upstream and downstream sampling

areas and AU and AD are the observed changes in the opacity of the

upstream and downstream sampling papers, respectively.

Arrestance determinations were made when the media was clean at

the beginning of the test, and at selected intervals of loading until

the intermittent advance of the media became representative of a steady

state operation. The arrestance determinations were made with Cottrell

precipitate only, while cotton linters were added during the loading

process in a ratio of 4 parts to every 96 parts of Cottrell precipitate

including the Cottrell precipitate 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.

The advance of the filter media was observed through a window in

the test apparatus by determining the position of a marker, attached

to the mat, relative to a yardstick mounted in the filter housing,

adjacent to the mat. A pilot light connected in parallel with the

electric motor enabled the operator to note the position of the media

and to record the pressure drop across the medium at the beginning and

at the end of each advance cycle. The advance cycle, which was actuated by a manually operated switch, began when the pressure drop across

the filter reached approximately 0.50 in. W.G* and stopped when the

drop was about 0.45 in. W.G.

The position of the media at the beginning of each advance cycle

was recorded as well as the corresponding cumulative dust load at the

time of advance. From this information a plot was made of the advance

- 3

-
of the media vs. dust load, and when the relation between the two

parameters became very nearly linear , more determinations of advance

as related to load were made, from which it was possible to draw a straight line from which the dust-holding capacity in grams/ft 2 was determined

The pressure drop across the media was recorded at the beginning

of the test, after each arrestance determination, after introduction

of each 20-gram increment of Cottrell precipitate and lint into the

test duct, and at the beginning and end of each advance cycle.

4. Test Results

Tests on the first roll were not completed when it became evident

that the dust-holding capacity would be considerably lower than

200 g/ft 2

, the minimum value specified by the General Services Administration for Type E, roll-type media. Tests on the second roll were

completed, but since the value for dust-holding capacity was only

slightly below 200 g/ft 2

, a third roll having appreciably more T.C.P.

adhesive was tested.

The initial results of the tests on the third roll, however,

showed that the roll had a lower dust-holding capacity than the second,

and the tests were discontinued. During the test of the third roll, the

dust, due to the heavy concentration of adhesive, failed to penetrate

into the media and rapidly formed a film on the upstream face which

caused the pressure drop to rise rapidly to 0.50 in. with a relatively

low dust load. This situation militated against a high dust-holding

capacity and preliminary observations indicated a very low capacity.

Following this initial test run on the third roll, the roll was advanced about 10 ft to new clean media, and the same procedures followed. The performance observed for the two portions of the third

roll, approximately 10 feet apart, was essentially the same.

The test results obtained on the second roll of the "Kleen-Air

media at the design air flow rate of 2000 cfm are summarized in Tables

2 and 3.

Table 2

Performance of the ''Kleen-Air' 1 Roll

Filter Media at an Air Flow Rate of 2000 cfm

Cumulative

'Dust Load

Total Advance

of Media

Pressure

Drop Arrestance

grams inches in. W.G. percent

0 0 0.200 69.0

629 15.75 0.504 85.2

883 24.00 0.502 84.1

1012 28.00 0.450 84.4

1157 32.50 0.448 85.0

1295 36.50 0.450 84.9

- 4

-
It will be noted that the arrestance of the clean filter media of

the second roll was 69 percent and the average arrestance under steadystate conditions was 84.7 percent using Cottrell precipitate in the

laboratory air as the aerosol.

Table 3

Dust Load, Mat Travel, and Pressure

Drop of "Kleen-Air" Glass Fiber Media

Dust Load Mat Travel Pressure Drop, In. W,G.

grams inches Before After

Advance Total Advance Advance

0 0 0 0.200 —

754 2.00 20.00 0.494 .452

816 2.00 22.00 0.500 .452

883 2.00 24.00 0.502 .448

945 2.00 26.00 0.496 .450

1012 2.00 28.00 0.498 .450

1085 2.50 30.50 0.496 .448

1158 2.00 32.50 0.498 .448

1224 2.25 34.75 0.500 .468

1287 1.75 36.50 * .450

1378 2.00 38.50 0.502 .450

*Value unknown

The first movement of the media was approximately 5 1/4 inches

and was initiated when the dust load was 375 grams and the pressure

drop was 0.498 in. W.G. The pressure drop at which advance cycles

were initiated after steady-state conditions had been reached (at 754

grams) ranged from 0.494 to 0.502 in. W.G. The average was 0.498 in.

W.G. At the end of the advance cycles, the pressure drops ranged from

0.448 to 0.468 in. W.G. with an average of 0.452 in. W.G.

The graph of Figure 1 shows the performance of the media for the

observations taken after steady-state conditions were established. It

will be noted that some of the individual points of observation do not

lie on the straight line. These deviations occurred partly because

the advance distance could be observed on the scale only to the nearest quarter-inch mark, and partly because it was not possible always

to close or open the manually-operated switch at exactly identical

pressure drop values. It is shown in the slightly extrapolated

straight line of Figure 1 that after 20 inches of mat travel, the

dust load was 750 g. and after 39.7 in. of travel, the dust load was

1400 g. Thus, a mat travel of 19.7 in. was caused by the introduction

of 650 g. of dust. The dust-holding capacity of the media was calculated by dividing the dust load increment by the incremental length of

advance in feet and by the width of the media.

Dust-holding capacity = -j- x ~ 198 g/ft^

- 5-
Because the value for dust-holding capacity was very close to the

requirement of 200 g/ft^, a ’’best fit" of a straight line through the

ten points was determined with the use of the "least-squares" technique. Using this line for the calculation, the value for dust-holding

capacity was found to be 198 g/ft^, a value which agreed with that

obtained with the use of the line on the graph.

The performance values determined for the best of the three rolls

of media submitted were 84.7 percent average arrestance and 198 g/ft^

dust-holding capacity. The current General Services Administration

requirement for average arrestance when Cottrell precipitate is used

as the test dust, is 75 percent and for the dust-holding capacity,

200 g / f 1 2

USCQMM-NBS-DC

- 6-
42

40

38

36

34

32

30

28

26

24

22

20

18

700 800 900 1000 1100 1200 1300 1400 1500 1600

MAT TEAVL^. VERSUS DUST LOAD

"KLEEN-AIR" GLASS FIBER AUTOMATIC

RENEWABLE FILTER MEDIA

DUST LOAD (GRAMS) Figure 1


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