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 July 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

People & Company News

Houston Ship Channel Man Overboard Swims to Island

The U.S. Coast Guard informs of the rescue of a 62-year-old man who was stranded on Atkinson Island, after he fell off his boat in the Houston Ship Channel near Sylvan Beach and swam to the island.

RS to Exhibit at SMM 2014

Russian Maritime Register of Shipping (RS) announced it will exhibit at Shipbuilding, Machinery and Marine Technology (SMM) International Trade Fair September 9-12, 2014 in Hamburg, Germany.

Green Marine, ACPA Partner to Reduce Environmental Footprint

Green Marine and the Association of Canadian Port Authorities (ACPA) have entered into a Memorandum of Understanding with the goal of jointly expanding efforts

Education/Training

VSTEP Delivers FMB Simulator to Danaos

Danaos Corporation purchased a NAUTIS DNV Class A FMB Simulator and Instructor Station for training of its fleet members.  The simulator will be delivered and installed

Maersk Drilling Rig Team Train Local Talent

Maersk Drilling says that its 'Mærsk Deliverer' rig team has initiated seven local acceleration programmes in Angola. The goal is to train and develop local talent

Mærsk Putting Valuable Experience to Good Use

The Mærsk Deliverer rig team has initiated seven local acceleration programmes in Angola. The goal is to train and develop local talent to take on increasingly

Salvage

Ohio River Reopens as Oil Spill Clean-up Progresses

A 15-mile section of the Ohio River was reopened for limited traffic on Wednesday as clean-up of a 5,000-gallon fuel oil spill continued, the U.S. Coast Guard said on Wednesday.

Search Suspended for Man Overboard near Cedar Bayou

The U.S. Coast Guard suspended its search Tuesday for a man who went missing after his shrimp boat overturned Monday near Cedar Bayou on the Houston Ship Channel.

Oil Spills into Ohio River from Coal Plant

The U.S. Coast Guard closed a 15-mile stretch of the Ohio River on Tuesday after at least five thousand gallons of fuel oil spilled from a 60-year-old power plant owned by Duke Energy near Cincinnati,

Marine Equipment

New Product Targets Manhole Safety

SafeEdge from Rustibus is a new and innovative system that provides safety for the crew and equipment when working around open manholes. This product is specifically

New Water-activated Life Raft

International Convention for the Safety of Lives at Sea (SOLAS), states commercial vessels must carry life rafts. In the majority of mass marine disasters globally,

Two MacGregor Subsea Cranes Ordered for Chinese PSVs

MacGregor, part of Cargotec, has secured a new contract from Chinese shipbuilder, Fujian Mawei Shipbuilding Ltd., for two 100-metric-ton active heave-compensated subsea MacGregor cranes.

 
 
Maritime Careers / Shipboard Positions Naval Architecture Offshore Oil Pipelines Pod Propulsion Port Authority Ship Electronics Ship Simulators Sonar Winch
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: 0.1464 sec (7 req/sec)