Quality control during production and application of roofing materials

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Quality control during production and application of roofing materials

Laaly, H. O.

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N21d

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1153

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National Research

Conseil national

Council Canada

de recherches Canada

BrnG

QUALITY CONTROL DURING PRODUCTION AND APPLICATION OF ROOFING MATERIALS

by H.O. Laaly

Appeared in

5th International Congress on Roofing and Waterproofing Association Internationale de I'ftancheite

Strasbourg, 1

-

3 June 1983 p. 253

-

267

Reprinted with permissi~n

DBR Paper No. 1153

Division of Building Research

This publication i s being distributed by the ~ i v i s i o n of Building R e s e a r c h of the National R e s e a r c h Council of Canada. I t should not be reproduced in whole o r in p a r t without p e r m i s s i o n of the original publisher. The Di- vision would be glad to b e of a s s i s t a n c e in obtaining such permission.

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. . . .

.

A l i s t of a 7

--.

m a y be o' i

of Builr Canada,

QUALITY CONTROL DURING PRODUCTION AND APPLICATION

OF ROOFING MATERIALS

H. 0. LAALY

National Research Council Canada, Division of Building Research.

SUMMARY

Quality control of roofing and waterproofing membranes occurs at four distinct stages: 1) characterization of raw materials with respect to degree of purity required for an established formlation

prior to production;

2)

control of processing and manufacturing

variables during production to permit necessary corrections before defective materials are produced; 3 ) testing and evaluation of

finished products for conformity with the established standards or as agreed upon by the supplier and purchaser; where the latter is a large company or a government agency, compliance with a specification

is usually required;

4)

control and inspection of workmanship quality

on the job site during the application in accordance with the architect's, engineer's or project manager's detailed job specification.

Stage 3 has already been discussed in the author's previous publications. This paper highlights some of the quality control

aspects and methods that could be implemented in stages 1, 2 and 4 .

Die Qualitatskontrolle von Bedachungsmaterialien wzhrend der Fabrikation und der Verarbeitung

von

H.O.

Laaly

ZUSAMMENFASSUNG

Die Qualitatskontrolle von Bedachungs- und Abdichtungsmaterialien ist in vier verschiedene Stufen unterteilt:

1) Kennzeichnung der Rohmaterialien in Bezug auf den Reinheitsgrad fiir

2 ) Kontrolle des Herstellungsverfahrens und der Produktionsvariabeln wiihrend der Fabrikation, damit die notwendigen Korrekturen unternommen. werden kznnen, bevor zu viele fehlerhafte Produkte fabriziert worden sind.

3 ) Priifung und Auswertung der Endprodukte gem2iss einer Normvorschrift oder einer zwischen Fabrikanten und G u f e r vereinbarten

Vertragsbedingung, wobei es sich beim letzteren um einen Grossk'iufer oder eine Regierungsbehgrde handeln kann.

4 ) Kontrolle und Inspektion der Verarbeitungsqualitat auf der Baustelle gemZss der spezifischen Projektvorschriften durch den Architekten, den Ingineur und den Bauleiter.

Der Verfasser hat sich mit der dritten Stufe in verschiedenen friiheren Publikationen befasst. Der vorliegende Artikel behandelt an Hand einiger ausgewahlter Beispiele hauptsachlich die Merkmale der

QualitZtskontrolle und der Verfahren, welche in Stufen 1, 2 und 4

angewandt werden k6nnen.

CONTR~LE

DE LA

QUA LIT^

DURANT LA FABRICATION ET

LA

POSE

DE

MAT~RIAUX

DE

COUVERTURE

par H.O. Laaly

R i s d

Le contrale de la qualit5 des revEtements dt6tanch6it6 s'effectue

en quatre 6tapes distinctes : 1) classification des matisres

premisres selon un degr6 de puret5 requis pour une foruulation 6tablie

avant la production ; 2) contr6le du processus de traitement et de

fabrication af in d'ef fectuer les corrections q u i s'imposent avant que

trop de mat6riaux d6fectueux ne soient produits ; 3) essai et

6valuation des produits finis pour vgrifier s'ils sont conformes aux

normes 6tablies ou convenues entre le fournisseur et l'acheteur ; si

ce dernier est une grosse entreprise ou une institution

gouvernementale, la conformit6 3 une exigence est habituellement

requise ; 4 ) contrale et inspection de la qualit5 d1ex6cution du

travail sur le site meme, en conformit6 avec les devis de

l'architecte, de 11ing6nieur ou du directeur des travaux.

L'6tape 3 a d6jZi fait l'objet de discussions dans d'autres

publications de l'auteur. Cette comuunication met en relief certaines

m6thodes de contr6le de la qualit6 qui pourraient etre mises en application aux 6tapes 1, 2 et 4 .

QUALITY CONTROL DURING PRODUCTION AND APPLICATION

OF ROOFING MATERIALS

H. 0 . LAALY

National Research Council Canada, Division of Building Research.

SUMMARY

Quality control of roofing and waterproofing membranes occurs at

four distinct stages: 1) characterization of raw materials with

respect to degree of purity required for an established formlation

prior to production;

2 )

control of processing and manufacturing

variables during production to permit necessary corrections before

defective materials are produced; 3) testing and evaluation of

finished products for conformity with the established standards or as

agreed upon by the supplier and purchaser; where the latter is a

large company or a government agency, compliance with a specification

is usually required;

4)

control and inspection of workmanship quality

on the job site during the application in accordance with the

architect's, engineer's or project manager's detailed job

specification.

Stage 3 has already been discussed in the author's previous

publications1

9

,

3 .

This paper highlights some of the quality

contro1,aspects and methods that could be implemented in stages 1,

2

and

4.

INTRODUCTION

Bitunen still counts as a major raw material, used widely for

roofing and waterproofing. Some 60 years ago, a technician in an

asphalt testing laboratory had to chew a sample from each batch of

*Associate Research Officer, Building Materials Section, Division of

Building Research, National Research Council of Canada.

airblown asphalt to determine the degree of oxidation by the ~.?xtent that it stuck to his teeth. The level of heating bitumen was

controlled on the job site by visually estimating the amount of smoke and vapor emitted from the kettle and detecting, with the nose, the odor of volatile components from overheated asphalt. The fingernails of the asphalt technologist were used to determine the softening point and penetration of oxidized bitumen. Evaluating it for use in roofing and waterproofing or asphalt pavement was obviously an art, rather than a science, and had to be learned over the years. All these approaches to quality control are now, it is hoped, only faded memories from the past.

With the introduction of hundreds of new roofing materials during the past two decades, the roofing industry experienced a drastic

change, not only in technology but also in the utilization of various polymeric and elastomeric-based materials and synthetic fibers for production of single-ply roofing and waterproofing membranes. This roofing revolution has necessitated a completely new quality control strategy. In order to assess the purity, homogeneity, particle size or molecular weight distribution of various components of new roofing materials, several sophisticated, highly precise instruments can be employed, not only during exploration and well drilling, but also during the refining of crude oil and the production of petrochemical intermediates and various raw materials used with them. The

Encyclopedia of

P V C ~

is the major source of informtion on quality

control of PVC products from raw materials to finished products.

Books by

i ate man^, or ton^

and stern7 constitute the present state-of-

the-art and give detailed information on raw materials and processing and testing of elastomric materials.

While the above-mentioned literature is a significant source of knowledge on testing and properties of rubber and rubberlike

materials, in practice only a few test methods are suitable for quality control testing, which must be quick, specific, econodc and informative. With increasing labor costs, it is now advisable to

utilize some of the.modern analytical instruments, depending on the

type of material and information required. Some of the techniques

useful for solving more complicated problems are: infrared (IR),

ultraviolet (UV), atomic absorption (AA), thermogravimetric analysis

(TGA)

,

thermonrechanical analysis

(TMA)

,

X-ray diffract ion

(XRD)

,

X-ray

chro-tography (GPC

1,

t r a n s m i s s i o n e l e c t r o n microscopy (TEM) and

scanning e l e c t r o n microscopy (SEM). _{I n i n d u s t r y , RCD and q u a l i t y}

c o n t r o l s c i e n t i s t s u s u a l l y c o o p e r a t e c l o s e l y s i n c e t h e o b j e c t i v e s of both teams a r e i d e n t i c a l , namely, p r o d u c t i o n of high q u a l i t y m a t e r i a l s w i t h s a t i s f a c t o r y performance a t t h e lowest p o s s i b l e c o s t .

Consequently, both can make use of t h e same equipment t o make i t s

purchase p o s s i b l e even f o r s m a l l companies.

I m p u r i t i e s i n raw m a t e r i a l s , p a r t i c l e s i z e and molecular weight d i s t r i b u t i o n of t h e r e s i n s , and p r o c e s s i n g c o n d i t i o n s d u r i n g

manufacture (such a s temperature, t i m e , moisture c o n t e n t ) a l l

c o n t r i b u t e t o t h e p h y s i c a l , chemical and mechanical p r o p e r t i e s of f i n i s h e d p r o d u c t s and could a f f e c t t h e performance of t h e f i n a l roof

d r a s t i c a l l y . Some t e s t s a r e a p p l i c a b l e t o more t h a n one s t a g e i n t h e

p r o d u c t i o n and a p p l i c a t i o n of new r o o f i n g m a t e r i a l s . From a w e a l t h of

q u a l i t y c o n t r o l p r o c e d u r e s , only a few s e l e c t e d examples w i l l be

d e s c r i b e d .

Raw M a t e r i a l s

The d e g r e e of o x i d a t i o n of blown a s p h a l t can be a s s e s s e d by i t s

d u c t i l i t y , v i s c o s i t y , s o f t e n i n g p o i n t and cone p e n e t r a t i o n . However,

t h e i n t e n s i t y of t h e carbonyl band i n t h e I R spectrum a t t h e 5.8 pm

r e g i o n can, w i t h i n a few minutes, provide t h e same i n f o r m a t i o n . A

combination of GC w i t h I R a n d / o r MS sometimes i s t h e most powerful

t o o l t o e n a b l e p r e d i c t i o n of polymer performance, c o n t r o l of r e s i n

c u r i n g time, m o n i t o r i n g of d e g r a d a t i o n , q u a l i t y c o n t r o l of incoming

m a t e r i a l s and a n a l y s i s of c o m p e t i t i v e products. Changes i n t h e

molecular weight d i s t r i b u t i o n of polymers, such a s p o l y v i n y l c h l o r i d e

(PVC)

,

p o l y e t h y l e n e (PE)

,

polypropylene (PP)

,

p o l y v i n y l a c e t a t e (PVA)

,

styrene-butadiene-styrene (SBS)

,

c h l o r i n a t e d p o l y e t h y l e n e (CPE) and polyurethane (PU), which a r e o f t e n used i n f o r m u l a t i o n of r o o f i n g m a t e r i a l s , a r e of paramount importance w i t h r e s p e c t t o t h e p r o p e r t i e s

of t h e f i n i s h e d membranes. The d e g r e e of t h e i r homogeneity and

f o r m a t i o n of a t r i d i m e n s i o n a l network i n a s p h a l t a f f e c t t h e f o l l a w i n g

p r o p e r t i e s of modified bituminous r o o f i n g membranes: t e n s i l e

s t r e n g t h , low t e m p e r a t u r e f l e x i b i l i t y , s t a t i c and dynamic puncturing,

a b i l i t y of l a p j o i n t i n g , m e l t v i s c o s i t y and c r a c k b r i d g i n g c a p a b i l i t y ,

t o name j u s t a few.

A

f exaqple. from t h e p u b l i s h e d l i t e r a t u r e 8 , s h o u l d i l l u s t r a t e

q u a l i t y c o n t r o l i n t h e polymer i n d u s t r y ( F i g . 1 ) . The GPC

chromatogram shows t h a t r e s i n s A and B have d i f f e r e n t m o l e c u l a r weight d i s t r i b u t i o n s . The f i n i s h e d p r o d u c t s made from t h e s e two r e s i n s may look very s i m i l a r , y e t d i f f e r i n t h e i r m e l t i n g p o i n t s .

~1gt-i Molecular Weight LOH

F i g . 1. Gel permeation chromatogram of r e s i n s A and B, showing m o l e c u l a r w e i g h t d i s t r i b u t i o n s 8

A d d i t i o n a l peaks i n a chromatogram a r e n o t o n l y i n d i c a t i v e of i m p u r i t i e s o r a d d i t i v e s i n a r e s i n , s u c h as p r o t e c t i v e c o l l o i d , s t a b i l i z e r , o r c o l o r a n t . Each peak can a l s o be c o l l e c t e d and i d e n t i f i e d by I R s p e c t r o s c o p y . The h i g h e r t h e m o l e c u l a r w e i g h t of a r e s i n , t h e h i g h e r i s t h e s t r e n g t h , v i s c o s i t y , r e q u i r e d p r o c e s s i n g t e m p e r a t u r e and c h e m i c a l r e s i s t a n c e . The w i d t h of m o l e c u l a r w e i g h t d i s t r i b u t i o n (MWD) d i c t a t e s t h e t e n s i l e s t r e n g t h and a l s o t h e p r o c e s s i n g b e h a v i o r of t h e polymer ( F i g . 2). Comparison of chromatograms i s a k i n d of q u a l i t y c o n t r o l . 2000 _-Tensile

strength vs. melt index

]

1600 1 I

Melt Index (log scale)

Fig. 2. T e n s i l e s t r e n g t h v s m e l t i n d i c e s 8

The p r e s e n c e of u n r e a c t e d monomer, low m o l e c u l a r w e i g h t compounds o r m o i s t u r e a l s o i n f l u e n c e s t h e p h y s i c a l a n d p r o c e s s i n g c h a r a c t e r i s t i c s of polymers. These e n t i t i e s have g e n e r a l l y s m a l l e r

m o l e c u l a r weigh and a p p e a r n e a r t h e end of t h e chromatogram. Using t h e peak h e i g h t , o r peak h e i g h t

f

x j w i d t h , t h e i r c o n c e n t r a t i o n can be

a s s e s s e d q u a n t i a t i v e l y .

i

Sometimes c a l i b r a t i o n w i t h i n t e r n a l s t a n d a r d s i s n e d e s s a r y .

Every compdnent i n c o r p o r a t e d i n t h e r o o f i n g f o r m l a r e q u i r e s i t s

own s p e c i f i c qu l i t y c o n t r o l procedure.

i

P a r t i c l e s i z e d i s t r i b u t i o n of r e c l a i m e d rubbed ( c r y o g e n i c ground) d i c t a t e s t h e d e g r e e of d i s p e r s i o n , s w e l l i n g and, f d n a l l y , t h e homogeneity of r u b b e r i z e d a s p h a l t and t h e r e q u i r e m e n t s f o r t h e l e v e l of h e a t i n g a n d t e m p e r a t u r e d u r i n g i t s

p r o d u c t i o n , s i n c e these a f f e c t t h e v i s c o s i t y and p e n e t r a t i o n of t h e f i n i s h e d p r o d u c t . . S y n t h e t i c r u b b e r s , s u c h as SBS, neoprene and b u t y l r u b b e r s , have oqher c h a r a c t e r i s t i c s , s u c h a s ozone r e s i s t a n c e and

I

i o d i n e number, d h i c h a r e i n d i c a t i v e of t h e d e g r e e of u n s a t u r a t i o n .

P r o c e s s i n g Quality C o n t r o l

D e g r a d a t i o n of polymer due t o e x c e s s i v e p r o c e s s i n g t e m p e r a t u r e w i l l l e a d t o changes i n i t s m o l e c u l a r weight. For example, u s i n g s u i t a b l e e x p e r i m e n t a l c o n d i t i o n s a d s e l e c t i n g t h e p r o p e r i n s t r u m e n t a t i o n v a r i a b l e s , one can f o l l o w t h e s t a g e s of p o l y e t h y l e n e o x i d a t i o n , a s i n d i c a t e d i n t h e f o l l u w i n g chromatogram: Polyelhylene oxldat~on I Slarl~ng rnater~al 2 F~rs: slage 3 Second slaqe 4 F~nal slage F i g . 3. Change i n m o l e c u l a r weight t h r o u g h s t a g e s of p o l y e t h y l e n e

The above c h r o 4 t o g r a m was o b t a i n e d u s i n g t r i c h l o r o b e n z e n e a s s o l v e n t a t 1 3 5 0 c . ~ I

I

c o l d - a p p l i e d l i q u i d membranes must p o s e s s a c e r t a i n v i s c o s i t y , depending on t h e i r i n t e n d e d u s e , which c o u l d be on v e r t i c a l ,

h o r i z o n t a l o r s l o p e d s u r f a c e s . I n a n e n u l s i o n , t h e s u r f a c t a n t must keep t h e produc4 s t a b l e a f t e r a t l e a s t two t o t h r e e f r e e z i n g and thawing c y c l e s . Solvent-based l i q u i d membranes must p o s s e s s a

r e a s o n a b l y f a s t d r y i n g t i m e , which c o u l d v a r y from a few h o u r s t o a few days. A s q u a l i t y c o n t r o l , h o t a i r oven d r y i n g a t 40°C i s

employed. Another r e l a t i v e l y q u i c k q u a l i t y c o n t r o l measure of l i q u i d a p p l i e d membranes i s low-temperature f l e x i b i l i t y (bend t e s t ) a t a d e s i r e d t e m p e r a t u r e . The a d h e s i o n p e e l t e s t on a s t a n d a r d i z e d s u b s t r a t e i s a l s o a v e r y i m p o r t a n t c o n s i d e r a t i o n i n a s s e s s i n g t h e q u a l i t y of a l l l i q u i d a p p l i e d membranes.

P r o c e s s i n g and q u a l i t y c o n t r o l of p r e f a b r i c a t e d e l a s t o m e r i c membranes, s u c h a s e t h y l e n e - p r o p y l e n e dienemonomer (EPDM), poly-iso- b u t y l e n e (PIB)

,

CPE, chloro-sulphonated p o l y e t h y l e n e (CSPE), Neoprene

( p o l y c h l o r o i s o p r e n e ) and b u t y l r u b b e r ( w h e t h e r p l a i n o r r e i n f o r c e d ) , s t a t e of c u r i n g ( v u l c a n i z a t i o n ) and d e s i r e d f l e x i b i l i t y of t h e f i n i s h e d membranes, v a r y s l i g h t l y . S c o r c h i n g ( p r e m a t u r e v u l c a n i z a t i o n ) , r a t e of c u r i n g ( c r o s s l i n k i n g and development of s t i f f n e s s ) and f i n a l l y t h e s t a t e of optimum c u r i n g , a l l a r e s t a g e s which must be s t r i c t l y c o n t r o l l e d . O v e r c u r i n g c a u s e s t h e m a t e r i a l t o c o n t i n u e t o h a r d e n , t h e modulus t o r i s e and t e n s i l e s t r e n g t h a n d e l o n g a t i o n t o f a l l . Sometimes ( p a r t i c u l a r l y i n t h e c a s e of n a t u r a l r u b b e r compounds) r e v e r s i o n o c c u r s w i t h o v e r c u r i n g , and modulus and t e n s i l e s t r e n g t h d e c r e a s e . The r a t e a t which t h e r u b b e r compound i s s h e a r e d o r formed a f f e c t s i t s p l a s t i c i t y . P r o c e s s i n g s t a g e s (mixing, e x t r u s i o n , c a l e n d e r i n g and molding) i n v o l v e d i f f e r e n t l e v e l s of s h e a r and, t h e r e f o r e , c a n be e x p e c t e d t o a f f e c t e a c h r u b b e r s t o c k d i f f e r e n t l y ( F i g . 4 ) . ' COMPRESSION EXTRUDING MOLDING MILLING/ INJECTION CALENDERING MOLDING

SHEAR RATE. SEC

-'

26 1

Flow r e s i s t a n c e of compounds 1 and 2, a s shown i n F i g u r e 4,

v a r i e s , depending on processing. T h e r e f o r e , t e s t s t o a s c e r t a i n t h e

p r o c e s s i n g c h a r a c t e r i s t i c s of a p a r t i c u l a r s t o c k i d e a l l y s h o u l d expose t h e t e s t sample t o s h e a r r a t e s i d e n t i c a l t o t h o s e encountered i n t h e a c t u a l p r o c e s s s t e p .

The p a r a l l e l p l a t e p l a s t o m e t e r i s widely used t o a s s e s s t h e

p l a s t i c i t y of rubber compounds. I n t h i s d e v i c e , a c y l i n d r i c a l

p r e h e a t e d rubber sample, 2 c c i n volume, i s p l a c e d between two

p a r a l l e l p l a t e s and a 5 kg load i s a p p l i e d t o i t f o r a s t a n d a r d p e r i o d

of time, u s u a l l y 3, 5 o r 10 minutes. The r e s u l t i n g t h i c k n e s s of t h e

specimen, i n m i l l i m e t e r s m u l t i p l i e d by one hundred, i s c a l l e d t h e

" p l a s t i c i t y number". T h i s method i s d e s c r i b e d i n d e t a i l i n ASTM

Method D 926. The degree of c u r i n g of r u b b e r s i s u s u a l l y a s s e s s e d by

u t i l i z i n g t h e O s c i l l a t i n g Disk Rheometer Curemeter i n accordance w i t h ASTM Method D 2084.

The u s e of s p e c i f i c i n d i c a t o r s can o f t e n g i v e c l u e s t o many

unknown phenomena. The use of "Neocarmin" s o l u t i o n 9 , a t e x t i l e f i b e r

i n d i c a t o r , w i t h t h e h e l p of a c o l o r c h a r t , can i d e n t i f y many

d i f f e r e n c e s , such a s t y p e , s u r f a c e t r e a t m e n t , degree of o x i d a t i o n and even t h e morphological d i f f e r e n c e s and d e g r e e of c r y s t a l l i n i t y of

v a r i o u s r e s i n s . A

UV

lamp o r a microscope w i t h p o l a r i z e d l i g h t could

be u s e f u l i n q u a l i t y c o n t r o l of raw m a t e r i a l s and f i n i s h e d products. The degree of embedment of g r a n u l e s on t h e s u r f a c e of

p r e f a b r i c a t e d , r e i n f o r c e d , modified bituminous membranes i s c o n t r o l l e d

by t h e v i s c o s i t y of t h e t o p c o a t i n g , shape and s i z e of g r a n u l e s and t h e e x t e n t of p r e s s u r e a p p l i e d d u r i n g t h e c a l e n d e r i n g of t h e membrane.

A loaded s t e e l b r u s h rubbing t h e s u r f a c e of t h e membrane sample t a k e n

d u r i n g p r o d u c t i o n c a n g i v e q u i c k i n f o r m a t i o n a b o u t t h e d e g r e e of g r a n u l e embedment.

Q u a l i t y C o n t r o l of A p p l i c a t i o n (Workmanship)

Even t h e b e s t membrane, i f n o t p r o p e r l y a p p l i e d , cannot g u a r a n t e e

sound r o o f i n g . For t h i s r e a s o n , t h e Canadian General S t a n d a r d s Board

Roofing committeelo h a s developed a p p l i c a t i o n s t a n d a r d s f o r e a c h group

of m a t e r i a l s . Every r o o f i n g p r o j e c t must be s u p e r v i s e d and t h e

i n s p e c t o r must be c e r t a i n t h a t a l l j o b s a r e c a r r i e d o u t a s s p e c i f i e d .

Sometimes t h i s does n o t happen i n p r a c t i c e and premature f a i l u r e i s

t h e r e s u l t . A r o o f i n g i n s p e c t o r s h o u l d c a r r y w i t h him a k i t comprised

s t r i p , small hand saw, s m a l l h a m ~ r , p a i r of p l i e r s , small hand b a l a n c e , pocket c a l c u l a t o r , camera, r u l e r a n d , f i n a l l y , t h e j o b s p e c i f i c a t i o n and d r a w i n g s , a l o n g w i t h h i s l o g book.

P r e p a r a t i o n of roof decks o r any o t h e r s u b s t r a t e , and e x c l u s i o n of m o i s t u r e i n t h e s y s t e m b e f o r e and d u r i n g a p p l i c a t i o n , a r e

paramount. A p a p e r i n d i c a t o r c o n t a i n i n g methylene b l u e c a n d e t e c t t h e p r e s e n c e of m o i s t u r e .

Immediate r e m e d i a l a c t i o n i s a r e q u i r e m e n t a f t e r t h e d e t e c t i o n of f a u l t y workmanship. There a r e s e v e r a l f a s t t e s t methods a v a i l a b l e which c a n b e c a r r i e d o u t i n t h e l a b o r a t o r y , of which t h r e e a r e d e s c r i b e d i n t h i s paper: g r a n u l e embedment, impact and h y d r o s t a t i c p r e s s u r e .

F i g . 5. Granule embedment t e s t

A l o a d e d , s p e c i f i e d s t e e l b r u s h can be used t o a s s e s s t h e d e g r e e of g r a n u l e embedment d u r i n g t h e m a n u f a c t u r i n g of s i n g l e - p l y membrane based on modified bitumen ( s e e CGSB 37-GP-56M). The r a t i n g can measure e i t h e r t h e w e i g h t of l o s t g r a n u l e s o r p e r c e n t a g e of exposed a r e a a f t e r g r a n u l e l o s s ( F i g . 5 ) .

I n t h e dynamic p u n c t u r i n g t e s t a 500-g weight

i s

dropped on a

membrane s u r f a c e a r e a of 1 cm2 and t h e e x t e n t of damage

i s

a s s e s s e d

( F i g s .

6

and

7 ) .

F i g . 6. Low q u a l i t y c o a t i n g a p p l i e d on low d e n s i t y PU foam c o u l d n o t r e s i s t t h e impact of 500-g l o a d from a h e i g h t of 5 cm.

F i g .

7.

A h i g h q u a l i t y l i q u i d membrane a p p l i e d on a h i g h d e n s i t y PU

foam was n o t damaged by t h e same t e s t from a h e i g h t of

A commercially a v a i l a b l e s t a i n l e s s

s

t e e 1 m i c r o f i l t r a t i o n a p p a r a t u s , c a p a b l e of w i t h s t a n d i n g p r e s s u r e up t o 6900 Kpa c o u l d be u s e d t o t e s t t h e h y d r o s t a t i c p r e s s u r e r e s i s t a n c e of w a t e r p r o o f i n g membranes. However, t h i s a p p a r a t u s i s t o o s o p h i s t i c a t e d and u n n e c e s s a r i l y e x p e n s i v e f o r m a t e r i a l s exposed t o t h e low w a t e r p r e s s u r e s a s s o c i a t e d w i t h b u i l d i n g s . C o n s e q u e n t l y , a p r e s s u r e c e l l p r e v i o u s l y used by t h e B u i l d i n g M a t e r i a l s S e c t i o n of DBR/NRCC was m o d i f i e d . The c e l l is made of t r a n s p a r e n t poly(methy1 m e t h a c r y l a t e ) ,

r i g i d enough t o w i t h s t a n d a p r e s s u r e of 21

-

28 Kpa, which i s s u f f i c i e n t f o r t e s t i n g w a t e r p r o o f i n g membranes. The c o s t i s o n l y

l / 1 0 t h t h a t of m i c r o f i l t r a t i o n d e v i c e s .

The c e l l c o n s i s t s of a bottom and a t o p p i e c e w i t h a machined c a v i t y a b o u t 1 3 mm d e e p and 75 mm i n d i a m e t e r i n t h e c e n t e r t o accommodate a s u p p o r t i n g w i r e mesh, a 100 mm d i a m e t e r specimen, and w a t e r on t o p of t h e membrane. I n t h e c e n t e r of t h e b o t t o m p i e c e i s a 7 mm d e p r e s s i o n t o r e c e i v e any w a t e r t h a t p a s s e s t h r o u g h t h e membrane. The t o p and bottom p a r t s a r e f a s t e n e d t o g e t h e r w i t h e i g h t 50 mm b o l t s , a s shown on t h e a t t a c h e d drawing. A neoprene O-ring f i t s i n t o g r o o v e s t o h o l d t h e membrane i n p l a c e and s e a l t h e c e l l . A h o s e c o n n e c t o r f o r a t t a c h i n g t h e w a t e r l i n e ( p r e f e r a b l y n y l o n o r p o l y e s t e r r e i n f o r c e d ) and a v a l v e t o m a i n t a i n o r r e l e a s e p r e s s u r e a r e screwed i n t o t h e t o p p i e c e , u s i n g t a p e t o p r e v e n t l e a k s .

A round lOO-mm d i a m e t e r specimen i s c u t f r o m t h e membrane u n d e r t e s t and p l a c e d on t h e s c r e e n s u p p o r t . I f t h e sample i s s u r f a c e d w i t h m i n e r a l g r a n u l e s , a 7 mm wide band of s i l i c o n e s e a l a n t i n t h e form of an 82 mm I D r i n g i s a p p l i e d t o t h e g r a n u l e s t o make t h e s u r f a c e of t h e membrane smooth where t h e O-ring c o n t a c t s i t . The c e l l i s t h e n

assembled ( F i g . 8).

A w a t e r h o s e i s a t t a c h e d t o t h e c o n n e c t o r u s i n g a h o s e clamp t o a v o i d l e a k s . The o t h e r end i s a t t a c h e d t o a w a t e r t a p and a p r e s s u r e gauge. The t a p i s opened a n d t h e a i r above t h e membrane r e p l a c e d w i t h w a t e r . The v a l v e on t o p of t h e c e l l i s t h e n c l o s e d and t h e w a t e r p r e s s u r e a d j u s t e d t o 21 Kpa. (A w a t e r p r e s s u r e r e g u l a t o r may be h e l p f u l . ) The w a t e r t a p s h o u l d be c l o s e d and l e f t f o r 1 h o u r , w i t h o c c a s i o n a l c h e c k s t o s e e t h a t t h e p r e s s u r e i s m a i n t a i n e d . A t t h e end of t h i s t i m e , t h e bottom of t h e membrane i s examined t h r o u g h t h e p l a s t i c f o r w a t e r d r o p l e t s . D e t e r m i n a t i o n of t h e p r e s e n c e o r a b s e n c e of w a t e r may be a i d e d by d i s a s s e m b l i n g t h e c e l l and p l a c i n g a p i e c e of w a t e r - t e s t p a p e r i n c o n t a c t w i t h t h e u n d e r s i d e of t h e membrane.

The t e s t i s r e p e a t e d w i t h a t l e a s t two more specimens of t h e membrane.

The membrane should p r e v e n t t r a n s m i s s i o n of w a t e r f o r 1 hour a t a water p r e s s u r e of 21 Kpa.

CONCLUDING REMARKS

The s a t i s f a c t o r y performance of any r o o f i n g o r w a t e r p r o o f i n g p r o j e c t depends on proper f o r m u l a t i o n of t h e raw m a t e r i a l s , and c o r r e c t p r o c e s s i n g c o n d i t i o n s t o produce membranes which meet o r exceed t h e s p e c i f i e d v a l u e s f o r t h e i r p h y s i c a l , mechanical and

e n g i n e e r i n g p r o p e r t i e s , a s measured by t h e s e l e c t e d t e s t methods. The membrane must be a p p l i e d a c c o r d i n g t o t h e r e q u i r e d a p p l i c a t i o n methods and j o b s p e c i f i c a t i o n s . Q u a l i t y c o n t r o l i s an e s s e n t i a l p a r t of

almost a l l of t h e s e s t a g e s . 7

Acknowledgement

The a u t h o r would l i k e t o thank V.S. Ramachandran f o r h i s v a l u a b l e s u g g e s t i o n s and H.E. Ashton f o r h i s e d i t o r i a l a s s i s t a n c e .

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L a a l y , H.O., "Methods of e v a l u a t i n g s i n g l e - p l y r o o f i n g membranes, " S i n g l e - P l y Roofing Technology, ASTM STP 790,

W.H. Gumpertz, Ed., ASTM, 1982, pp 65-77.

L a a l y , H.O. and Ashton, H.E., "Methodology and T e s t P r o c e d u r e s f o r E v a l u a t i n g New M a t e r i a l s " i n Vol. 2, pp 24-32, Proc. Second I n t e r n a t i o n a l Symposium on Roofs and Roofing, B r i g h t o n , Eng.

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S e p t 1981, J . O . May, Ed., Soc. of Chem. Ind., London SWlX 8PS, England, 1982.

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s u b s t a n c e s , " MacLaren & Sons L t d . , London, o r John Wiley 6 Sons,

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N a t u r a l and S y n t h e t i c , " MacLaren a n d Sons, L t d . , London, Palmerton P u b l i s h i n g Co., I n c . , N.Y., 1967. Waters A s s o c i a t e s , M i l f o r d , .Mass., "Know more a b o u t y o u r

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"Neocarmin" Reagent ( F i b e r i d e n t i f i c a t i o n ) , Fesago Chem. F a b r i k , D r . G w s l e r , G. m.l.H., D-6902 s a n d h a u s e n l ~ e i d e l b e r g , W.

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