Safety Bulletin: Kovar-Sealed Glass Vacuum Viewports

Document #:

LIGO-M080310-v1

Document type:

M - Management or Policy

Abstract:

Investigation of the May 2008 vacuum accident at Virgo revealed important information about the safety of certain standard commercial viewports. The viewports in question are those made of Corning 7056 or Kodial glass sealed directly to Kovar alloy, which is in turn welded into a stainless steel vacuum flange (usually a ConFlat type). These may be called “Kovar-sealed”, “zero-length,” “low-profile” or “zero-profile” viewports in catalog descriptions. This document describes how to identify the faulty viewports.

Files in Document:

• M080310-00.pdf (31.3 MB)

Other Files:

• sketch to illustrate M080310-00 viewport safety bulletin.pdf (15.7 kB)

Topics:

• Document Migration from the old DCC

Authors:

• Michael Zucker

Keywords:

Safety Vacuum_Equipment

Notes and Changes:

adding a sketch to help identify the faulty viewports

Referenced by:

• LIGO-E1300438: Repository for Viewport Test Results
• LIGO-D2300135-v4: SPECIFICATION CONTROL DRAWING: LIGO, VE, COMFORMANT VIEWPORTS.