There is a general rule that says, any headline that ends in a question mark can always be answered, no. So, small detail? No.
What is the opposite of an academic? I think its me, because I am looking for answers to problems I experience, I am an empiricist. Also I am trying to expand my knowledge and add value in the world of property design and construction. This is a slightly bizarre world with;
- extreme ranges of competence at all levels;
- clients who want high performance for the same price as incompetence;
- cronyism and lobbying that would make politicians blush.
Empirical results Vs academic theory is what matters to me when Commissioning a building, I want to know what does and doesn’t work. Quality in design, construction and Commissioning matter, IMHO. Wow, I sound like a grumpy old man! However I believe, to affect change and quality, every little thing matters and everyone can make a difference.
In the previous two posts I looked at the importance of valve location, installation and authority. I have tired to bring this all altogether in a cooling coil detail (which also works for heating) that is optimized for Commissioning and facilities management. This is a whole life perspective not a first cost perspective.
When reviewing this coil detail (see attached), remember we live in a world where there is little agreement on good practice, valve location, valve authority, number and location of test points and flushing methodologies. This detail is what I would like to see to enable effective commissioning and diagnostic testing. My notes on the attached coil detail are;
1. Flushing points are required as located to enable system flushing and local back flushing of the coil.
2. The connection of the flow pipe to the coil should always be to the “air leading” side of the coil.
2. YES! The control valve should be in the return pipe, also please check valve authority calculation or confirm by RFI.
4. Pressure connection points to measure the pressure drop across the strainer, coil and control valve cost very little but provide a life time of commissioning and diagnostic use.
4. Temperature gauges are useful for quick diagnostics and should be installed so that they can be read easily (without obstruction or ladders) with the correct range for the system application.
5. Insulation should be vapour sealed (CHW) but allow access to pressure connection points and commissioning valves without the need to cut and reinstall insulation.
6. Commissioning valve and control valve to be installed with 10 straight pipe diameters upstream and 5 straight pipe diameters down stream to ensure optimum performance.
7. Isolating valves to be high performance butterfly valves. These valve types provide rapid isolations i.e. 90 degree movement to close plus there is an instant visual verification that the valve is open or shut. Important for mission critical applications.
8. Install commissioning valves and pressure test points with connection points face up or on a vertical plane to prevent dirt collection issues.
1. Coil pressure drop to be measured and recorded in the commissioning report with the system balanced.
2. Control valve pressure drop to be measured and recorded in the commissioning report with the system balanced.
3. Clean strainer pressure drop to be measured and recorded in the commissioning report with the system balanced.
Next week, on to lighter matters in the realm of fantasy….