Week2 day 1 in school

April 2020 Sunday 12 Easter Day covid19 lock down. School plan. Finish all the questionnaire from pink binder. Starting with book 4. Learn, memorize. Test yourself after till you remember everything.

1. Week 2 book 4 ANSI and others. 
2. Week 3 theory , prism, calculation optics. Book 3
3. Week 4 book 3 and mix of book 2 
4. Week 5 book 2 
5. Week 6 noc study guides . 

Testing part 2

High velocity spectacles shall be capable of resisting impact from a 6.35 mm ( 1/4 in) diameter steel ball traveling ata velocity of 45.7 MPs ( 150 FPS).

• Setup of alderson headform positioned before a firing chamber that will release a 1/4 - inch steel ball to impact the lens at a velocity of approximately 150 ft/sec. 

Testing

High impact: frame shall be capable of resisting impact from pointed projectile weight 500g (17.6 oz)  droppedfrom a height of 127 cm (50 in).

• Depiction of alderson headformas used in high-mass impact testing of spectacle frames .
• A 500- gram steel missile is dropped from 50” , with the guide tube ending 7.1 inches above the lens itself.

Major differences about safety eyewear

• Rx safety lenses must be 3.0 mm thick 
• Marked with manufacturers monogram.
• Drop ball test on rx lenses in safety frame call for 1- inch diameter steel ball dropped from a height of 5”.
• Drop ball tests on rx lenses in dress eyewear call for a 5/8 “ diameter steel ball dropped from 50”.
• Safety frame marked with manufacturer’s trademark and Z87 in size 
• Safety eyewear has side shields to protect impact hazard.
• Safety frames has 2 impact tests - Testing devices call Anderson headform