Fire protection engineering design/contract documents, including clear drawing notes and specifications, can go a long way toward ensuring the applicable code requirements are met. One example is the Underground Material and Test Certificate.
We often have projects where the normal working pressure in the private underground supply piping is 175 psi based on the jockey pump stop pressure. Our design specifically indicated a hydrostatic test pressure of 225 psi (normal working pressure plus 50 psi) in accordance with the requirements of NFPA 24:
NFPA 24 section 10.10.2.2.1* All piping and attached appurtenances subjected to system working pressure shall be hydrostatically tested at 200 psi or 50 psi in excess of the system working pressure, whichever is greater, and shall maintain that pressure at +/- 5 psi for 2 hours.
In one recent case, the underground installer, the general contractor, and the local AHJ were not intimately familiar with the engineer of record issued design/contract documents. The underground contractor only hydrostatically tested the private underground supply piping system to 200 psi for two hours, the general contractor witnessed the test, and the AHJ accepted the documentation without exception.
Following the test, but after the concrete floor slab was poured, we were asked to review the Underground Material and Test Certificates and we noticed the discrepancy. As a result, we advised that the private underground supply piping be retested to the correct pressure. And while 25 psi does not sound like much, we have observed serious leaks developing at 225 psi on systems that had previously withstood a 200 psi hydrostatic test.
Obviously, the best time to clarify a requirement is before it is missed during construction. What do you think would be most effective to ensure design requirements are not being overlooked:
- Make the text larger on the drawing notes;
- Coordinate with the Civil Engineer to have the test requirements added to their drawings;
- Organize a preconstruction meeting to outline the requirements;
- Offer a verbal reminder during weekly construction meeting (if you attend);
- Make a written request for test certificates with requirements clarified during the installation of the system;
- Make an E-mail request for test certificates timed to coincide with appropriate scheduled milestone date; or
- Some combination of the above?
We have found that the earlier you can get information in the hands of the people performing the work, the more successful the outcome. So, we “Think Upstream” by communicating early, often, and so that you cannot be misunderstood. Then, trust but verify.
“There comes a point where we need to stop just pulling people out of the river. We need to go upstream and find out why they’re falling in.” ~ Desmond Tutu