Category Archives: Construction

Natatorium Acoustics

Consideration must be given to acoustical problems that develop in a natatorium.  Structural features and finish materials should be selected that will absorb sound and reduce noise levels.  In this regard, it is recommended that acoustical building materials be used on the walls and in the ceiling of the natatorium and that other noise dampening features be included, if possible. 

Ceiling decks have been successful when a perforated epoxy coated galvanized structural steel panel is used.  Further acoustical enhancement occurs if the panel is backed with polyethylene encapsulated fiberglass or closed cell styrofoam battens. Ithaca College Professional (3)

A different approach for enhancing acoustics for a concrete roof system is hanging acoustical baffles between the concrete beams or T’s.  Suspended acoustical panels made of fabric- covered fiberglass, aluminum, closed cell rigid plastic foam board or a combination of these are functional.  Not only do these units serve a technical purpose but they can also add color to the space.  All must be corrosion resistant. 

As with other materials in a natatorium, acoustical wall and ceiling must be corrosion resistant and interface with a vapor barrier, if necessary.

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Model Aquatic Health Code (MAHC) Review

Many people have been asking:

What is the current status of the MAHC and what is the best web site address to hit to see the current status of the modules for comments?

Here’s a link to the CDC’s webpage so you can check the status on each module.

http://www.cdc.gov/healthywater/swimming/pools/mahc/structure-content/index.html

Here’s a list of what we know has happened so far

Disinfection Water Quality:        Second Post after public comment 1/24/14

Regulatory Module:                      Second Post after public comment 1/24/14

Facility and Design:                      Second Post after public comment 12/16/13

Risk Management                         Second Post after public comment 7/23/13

Facility Maintenance                    Second Post after public comment 7/2/13

Monitor and Testing                     Second Post after public comment 6/05/13

Contamination Burden                Second Post after public comment 6/05/13

Fecal Contamination                    Second Post after public comment 5/30/13

Operator Training                         Second Post after public comment 04/08/11

Preface                                             Second Post after public comment 11/10/11

Recirculation/Filter System        First Post 7/02/13  They have not posted public comment or reposted after update.

Ventilation                                      First Post 4/13/11  They have not posted public comment or reposted after update.

 

Don’t forget to get your comments in!

Pool Plaster Spalling – Improper Installation or Poor Water Chemistry?

11_viewpointPool plaster is made up of cement, sand and water.  It is commonly troweled onto a concrete pool shell in 3 to 5 separate passes – the early passes to place the material and the later passes to create a smooth final finish.  After plaster is troweled, excess water will bleed to the surface.  Bleed water then evaporates from the surface.  There are two common mistakes made during troweling.  First, if troweling is completed when bleed water is present it will force water back into the plaster paste which causes excessively high water to cement ratio which weakens the finished surface.  Second if troweling is completed late after the surface is too dry a crust will form with a wet paste underneath.  This will create a weakened zone subsurface.  This typically happens on dry, hot days with low humidity and wind.  If this happens, the finished surface will look fine and even last awhile if the pool is full of water.  However, when the pool is emptied, a 16th to an 8th inch layer of plaster will flake off or spall in small areas or spots.  Pool plaster spalling is a rare occurrence but most often happens in areas that are challenging to apply plaster including step areas, main drains, and shallow areas.  Often, the first reaction to pool plaster failure is to blame the pool water chemistry however improper installation is typically the cause of pool plaster spalling.

Revised MAHC Module Posted: Facility Design and Construction

Centers for Disease Control and Prevention (CDC) sent this bulletin at 12/16/2013 04:05 PM EST

Model Aquatic Health Code

December 16, 2013

Thank you for your interest in the Model Aquatic Health Code (MAHC), a collaborative effort of public health, academia, and industry working to protect individuals, families, and communities from preventable waterborne diseases and injuries through evidence-based guidance. Read below for the latest information.

New

The Facility Design and Construction Module has been revised and re-posted after the first public comment period. View the revised module and the response to comments document.

Reminders

Each module has a short synopsis or abstract highlighting the most critical recommendations.

You can monitor the status of all modules on the MAHC website.

MAHC Recirculation Systems and Filtration (CH Comments)

CDC posts the Model Aquatic Health Code’s module for Recirculation Systems and Filtration for public comment with a closing date of October 9, 2013. Hydrologicblog posted this announcement with the supporting documents.

Recirculation Systems and Filtration

The Counsilman – Hunsaker team posted a group response in support of the public comment requirements. This response can be viewed at the below link.

MAHC Recirculation Systems Filtration comments