Phase 2—Screening test Clause Samples
Phase 2—Screening test. (1) Intro- duction and purpose.
(i) Phase 2 meas- urements provide approximate solar photolysis rate constants and half-lives of test chemicals in PW and SHW. If the photoreaction rate in SHW is sig- nificantly larger than in PW (factor of > 2X) then the test chemical is subject to indirect photoreaction and Phase 3 is necessary. Phase 2 data are needed for more accurate Phase 3 measure- ments, which require parallel solar ir- radiation of actinometer and test chemical solutions. The actinometer composition is adjusted according to the results of Phase 2 for each chem- ical, to equalize as much as possible photoreaction rate constants of chem- ical in SHW and actinometer.
(ii) In Phase 2, sunlight photoreaction rate constants are meas- ured in round tubes containing SHW and then mathematically corrected to a flat water surface geometry. These rate constants are not corrected to clear-sky conditions.
Phase 2—Screening test. (1) I n tro- duction and purpose. ( i) P h a se 2 m e a s- ur e m e n t s p r ovide a pp r oxi m a t e sol a r p h o t ol y s i s r a t e co n s t a n t s a n d h a lf- lives of t es t c h e m ic a l s i n P W a n d S HW. If t h e p h o t o r e a c t io n r a t e i n S HW i s s ig- n ific a n t l y l a r ge r t h a n i n P W (fa c t o r of > 2X) t h e n t h e t es t c h e m ic a l i s s u bjec t t o i n di r ec t p h o t o r e a c t io n a n d P h a se 3 i s n ecess a ry . P h a se 2 d a t a a r e n eeded fo r m o r e a cc ur a t e P h a se 3 m e a s ur e- m e n t s, w h ic h r eq u i r e p a r a llel sol a r i r - r a di a t io n of a c t i n o m e t e r a n d t es t c h e m ic a l sol u t io n s. T h e a c t i n o m e t e r co m posi t io n i s a dj u s t ed a cco r di n g t o t h e r es u l t s of P h a se 2 fo r e a c h c h e m - ic a l , t o eq u a lize a s m u c h a s possible p h o t o r e a c t io n r a t e co n s t a n t s of c h e m - ic a l i n S HW a n d a c t i n o m e t e r .