IMCA Publishes Acrylic Plastic Viewports Guidance

press release
Thursday, February 09, 2012

Acrylic plastic viewports in diving systems have been in satisfactory use for a number of years. However, the development of testing them by polarized light showed that there are various misconceptions about them.


The International Marine Contractors Association (IMCA) has just released updated guidance on the topic. An initial guidance note which sought to correct these misconceptions was initially prepared as AODC 030 in 1986 following advice from Det Norske Veritas (DNV). Now a revised document has been produced by IMCA through the Safety, Medical, Technical & Training Committee of its Diving Division Management Committee as part of its planned phased review of AODC guidance notes, which are then issued as IMCA guidance.
 

“Acrylic viewports are used in many pressurised systems under a variety of conditions world-wide and this document has been produced to provide general guidance,” explains IMCA’s Technical Director, Jane Bugler. “It includes additional guidance on deterioration compared to its predecessor, and identifies a reference document which perfectly complements it.
 

“That document is the ASME ‘Safety Standard for Pressure Vessels for Human Occupancy: In-Service PVHO Acrylic Windows Guidelines, PVHO-2: 2003’ which provides technical criteria and guidelines for the in-service inspection, care, repair or replacement, testing and recertification of pressure vessels for human occupancy (PVHO) acrylic windows.”
 

The IMCA document comes to five specific conclusions:
 

  • Acrylic plastic viewports should be properly certified and marked prior to use.
  • It is generally agreed that they should be replaced after 10 years of service (PVHO-2: 2003 provides additional guidance when determining the length of service.
  • Examination of an acrylic plastic viewport by polarised light after the viewport has been in service is of very limited use, as all such viewports will show evidence of inbuilt stress.
  • The use of polarised light to check that acrylic plastic viewports are correctly mounted and evenly pre-stressed is not a simple matter and should not be used as a principal test
  • When mounting an acrylic plastic viewport, it is critical, especially when installing new ports in old pressure vessels, to check that the housing is the correct dimension and that the viewport and any sealing gaskets or O-rings are properly seated and of the correct size. A torque wrench should be used to correctly tension fixings diametrically to the manufacturer’s specification when replacing retainers.

 

IMCA’s new publication IMCA D 047 is available for free downloading from the IMCA website at www.imca-int.com with additional printed copies available to members at £2.50 and non-members at £5.00 (plus 20% for delivery outside Europe).
 

Maritime Reporter January 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

People & Company News

Matson Announces Quarterly Dividend

Matson, Inc. declared a first quarter dividend of $0.17 per common share, the company’s board of directors announced. The dividend will be paid on March 5, 2015

Hogan Named VP at Newport News Shipbuilding

Rob Hogan has been appointed vice president of manufacturing at the Newport News Shipbuilding division of Huntington Ingalls Industries (HII), the company announced.

Kongsberg Expands Louisiana Office, Training Facility

Kongsberg Maritime has purchased approximately 5.2 acres for new construction on an 82,980 sq ft office and training facility. Construction on the James Business

Education/Training

BCG Delivers Training Upgrades

Buffalo Computer Graphics delivered upgrades to Columbia Pacific Maritime in Portland and The River School in Memphis,. The River School ordered additional laptop

Australian Tall Ship Rounds Cape Horn

The Royal Australian Navy operated Sail Training Ship Young Endeavour rounded Cape Horn on Australia Day, 36 days into a 12-month circumnavigation of the world.

Cutlass Express 2015 Commences

Maritime forces from East Africa, South Africa, Europe, Indian Ocean nations, the United States and several international organizations began the fourth iteration

Salvage

Fugitive Treasure Hunter Arrested in Florida

An Ohio man who recovered as much as $400 million in gold from a shipwreck has been arrested in Florida after two years on the run and was scheduled to appear in federal court on Wednesday.

ms Veendam Rescues Pilot Off Maui Coast, Hawaii

On Sunday, Jan. 25, 2015, at 5:21 p.m. local time while en route to Lahaina, Hawaii, Holland America Line’s ms Veendam answered a request for assistance from

ASA Mission Statement Revised to Expand Reach

The American Salvage Association has revised its mission statement to increase its area of influence beyond North America, complemented by a new logo that reflects the expanded direction.

Marine Equipment

Kongsberg Expands Louisiana Office, Training Facility

Kongsberg Maritime has purchased approximately 5.2 acres for new construction on an 82,980 sq ft office and training facility. Construction on the James Business

First Container for LNG Hybrid Barge

The HUMMEL (bumblebee) LNG Hybrid Barge will enable Becker Marine Systems to supply low-emission power to cruise ships lying at port in Hamburg. The first container

IntelliJet: Cleantech Propulsion for High Speed Applicatios

IntelliJet Marine, Inc. will present a paper on propulsion and computer simulation for sustainable high speed boats and ships at ASNE Day 2015.   Jeff Jordan

 
 
Maritime Security Maritime Standards Naval Architecture Navigation Offshore Oil Pod Propulsion Salvage Ship Electronics Ship Repair Sonar
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.2694 sec (4 req/sec)