Letters To The Editor - February 2008
When the Code Doesn't Work: Another PerspectiveI am writing to comment on Julius Ballanco’s recent column, “When the Code Doesn’t Work” (Nov. 2007). Unfortunately, his report does not include the facts as viewed by this office. Hopefully, this information will assist in your readers’ understanding of the resulting decision and the reasons supporting that decision.
The Bureau of Construction Codes, State of Michigan, requested standards conformance documentation several years ago for no-hub cast iron soil pipe used in a project inspected by this office following a request from a designer related to state-inspected school projects. Several suppliers of product manufactured in China who import these materials provided test reports that were used in obtaining product listings to support the acceptance of these products.
The original lab reports used in these listings for the importers contained serious discrepancies. Over an extended time period, the test reports were revised in order to address errors cited in evaluations to gain the commission’s approval. It became evident that the role of this agency was being misapplied as a reviewer of the reports in order to identify errors for corrections.
This agency is responsible for the evaluation of products and material for use in the State of Michigan, not as a third-party evaluator of reports. The reporting errors resulted in the Michigan State Plumbing Board establishing acceptance criteria to assure standard conformance.
The criteria and standards conformance has not been demonstrated to date. One of the most basic illustrations is that two Dimensional Inspection Reports separated by one year and 10 months are identical in every dimension to hundredths of an inch from one of the manufacturers. This was brought to the attention of all parties and has not been addressed to the satisfaction of this office or the State Plumbing Board.
This agency has filed a formal complaint with ANSI to resolve these issues in an effort to assure consumers have acceptable products conforming to code-required standards. Ballanco’s article referred to this office being uncomfortable with the submitted materials. This is an unfortunate characterization. It was demonstrated during the evaluation that the products do not conform to the required standards. Unfortunately, this greater analysis has led to the bureau’s lack of confidence in the conformance and reporting processes.
Robert G. Konyndyk, Chief
Importance of the User CommunityI read Dan Holohan’s PM Engineer column on a regular basis because it is never boring, especially his article called “Generations”-which I re-read recently. Most of my experience with heating does not involve steam. Since 1959, I have been involved with design and construction of life-support systems for marine organisms.
Having worked on projects in North America, Europe and a number a of intriguing seaside resorts in the Middle East and North Africa, I feel fortunate to have had a wonderful opportunity to observe and learn philosophies and technologies used by different cultures in the manipulation of water-hot and cold and often corrosively salty. I lived in Italy from 1971 to 1981, and when I first began working there I was surprised at the sophistication of hydronic systems already available for home heating-stuff that only recently became available in the U.S.
I found that it was often advantageous to personally participate in the simple plumbing work such as hanging lines, sweating joints and cementing PVC pipe alongside the local crew so as to evaluate their technical competence, and be sure that things were going to work as we intended. There is no valid substitute for the dirty hands experience gained in the practice of construction and maintenance by the guy who will some day be drawing up the specs.
As you suggest, the legitimate practitioners should learn to communicate with the user community. But I would insist that this be in an unbiased form that does not limit the “teachers” discourse to a single proprietary approach.
Port Norris, NJ
More Than One Type of PipeI’m writing in reply to an article that Julius Ballanco wrote for your most recent Fire Protection & Design Supplement (March 2007) called “Piping a Residential Sprinkler System.” I thought the article was very informative, and I hope that it will be widely read and quoted. However, in future writings I would like to suggest that your magazine consider referring to the “orange pipe” by a generic description of CPVC fire sprinkler pipe and fittings rather than the trade name of Blazemaster. While it is understandable that Blazemaster is the Kleenex of CPVC sprinkler pipe, there are other fully approved products on the market that do not license the Blazemaster name. I represent such a company, Spears Mfg., which uses the trade name FlameGuard.
Hydraulic SeparatorsI have been using hydraulic separator/buffer tanks for more than ten years. In the article on Hydraulic Separation by John Siegenthaler (Sept. 2007,) I consider Figure 10 (below) a grave mistake in design. He should be drawing the supply toward the system distribution off the bottom of the tank and the return into the top of the tank. The way it is drawn will only encourage excessive temperature stratification and potential direct boiler feed toward the system (unless this is his objective). The primary system stays as it is drawn.
From this basic system that draws from the bottom of the tank, many different take-offs or designs can start to occur, including multiple heat sources without creating future problems. The tank can be used with an indoor/outdoor boiler or multiple-staging boiler or with high temp atmospheric boilers using larger buffer tanks to avoid short cycling. The way it is drawn limits design capabilities, and I believe it will lead to misinterpretations.
Global Unitech Imports Inc.
John Siegenthaler Responds:
Gerry raises a good point on stratification. If the flow rate in the boiler circuit was the same as in the distribution system, there would be minimal mixing in the buffer tank. It would still function as a hydraulic separator between the circuits, but its thermal buffering effect would be small. His concept of drawing water from the bottom of the buffer tank would reduce stratification within the tank by creating a downward flow through it.
I think the key to the situation is how the boiler is controlled. As shown, boiler modulation would be based on the supply temperature to the distribution system. If the flow rate in the distribution system was higher than that in the boiler, there will be some upward flow in the buffer tank, which would help “turn over” its water volume and allow its thermal mass to “participate” in the operation of the system. If the boiler flow rate is higher than the flow in the distribution system, there will be a net downward flow in the buffer tank, which will again allow its mass to participate in system operation. Only when the two flow rates are equal will there be minimal mixing effect in the tank.
Another possibility is to modulate the boiler output based on maintaining the buffer tank at either a fixed setpoint or variable setpoint temperature based on outdoor reset control. In this case, a sensor would be located within the buffer tank, probably near its center. This sensor placement would ensure the mass of the buffer tank participates in the system.
The boiler would be responsible to maintain the temperature of this sensor between an upper and lower limit set by the differential of the controller. This control action would be in effect regardless of the draw on the tank from the distribution system.
In effect, the buffer tank simply becomes a source of water at the supply temperature currently required by the distribution system. The boiler’s modulation would vary depending on the rate of energy extraction from the tank by the distribution system.