HVAC / HYDRONICS
BY GEORGE LANTHIER
exterior nipple and vent cap from the vent pipe and plug it .
Then I remove the fill device and cap and put a nipple in there that ends in a Schrader fitting so I can attach my compressor , Figure 2 or hand pump , Figure 3 . One of my old installation trucks was equipped with a compressor from an air brake system . We rigged it up with a clutch and it was great for doing testing on oil tanks and new system installs . It also came in real handy for charging large diaphragm-type expansion tanks .
Now I turn on the compressor and charge the oil tank . NFPA31-8.8 says that I must have at least 5 psig , but no more than 10 psig for the test . I have to leave it this way for 30 minutes with no drop in pressure or “ for sufficient time to complete visual inspection of all joints and connections ” per NFPA31-8.11 .
When I complete the pneumatic test , I touch up all and any scratches I ’ ve made on the tank and paint the piping with “ at least one coat of organic alkydresin type or asphalt base type paint on the exterior surface to protect it from atmospheric corrosion ” to comply with UL80-13.1 . A lot of us in the trade have moved to painting and actually buying tanks in some color other than black . If you buy or paint a tank gray or light blue it ’ s amazing the esthetic effect that it has on a homeowner . It ’ s especially dramatic when the tank is in a new , unfinished basement and the realtor is already hesitant to sell a house with oil-
Figure 3
heat , it makes the tank appear to disappear . Really . Try it some time .
Let ’ s look at some multiple tank installations next . You may have noted that I didn ’ t go into pipe sizing in the last article for the fill and vent . We are going to do that now .
First of all , and I can ’ t stress this enough , NFPA30 , NFPA31 and UL-80 are essentially the law of the land when it comes to tanks except where there may be some local ordinances and regulations that say otherwise . Find out what they are before you begin the job .
Before 1997 almost all of the country piped tanks in 1-1 / 4- inch fill and vent pipe sizes . Then in NFAP31-1997 the sizes were changed to 2-inch . That move was not very popular and was rescinded in 2001 . Some states , like Massachusetts , Rhode Island and Maine fought that change and never went along with it , a smart move in my opinion . However , there have always been exceptions .
In New York City and elsewhere it ’ s mandatory that you pipe the tank with a 2-inch fill and a 1-1 / 4-inch vent . The funny thing is that NYC officials can ’ t tell you why , they just tell you “ we always did it that way .” In other situations states may elect not to adopt the latest version of a standard or may elect to adopt only parts of it . In my training sessions I stress that although I call it the “ inch-and-a-quarter rule ,” it ’ s actually really much simpler than that . The way I remember is that “ a fill may never be larger than a vent , and the vent must be 1-1 / 4 inch minimum .” This is all
Figure 2 in regard to a single tank of less than 660 gallons capacity . What about those multiple tank jobs ?
First of all , it should be noted that in Massachusetts , oilmen fought for and still maintain the right to install up to 1,320 gallons of storage in an unenclosed area and to a single burner . Under NFPA31-7.5.13 you cannot have more than “ 1320 gallons of fuel storage capacity connected to any one oil-burning appliance ” if the tanks are connected together . However , if you put in a “ Listed ” or “ Engineered ” fuel storage system you can have a maximum allowable fuel storage capacity of 1,375 gallons . What it ’ s going to cost you and your customer to get that “ engineered ” system signed off by a professional engineer ( PE ) is another matter .
Let ’ s talk about the most common install : two oil tanks of 275 or 330 gallons each . Basically , some ground rules that almost look like “ common sense .” The tanks must be installed following all of the guidelines we ’ ve already covered for a single tank install .
Now we get into the biggest controversy in oil tanks and piping out there . Up until about 1950 or so the following piping drawing was legal everywhere , including Massachusetts . Then , Massachusetts rescinded it . In 1995 Massachusetts allowed it again as the state prepared to adopt all of the NFPA
Figure 4
46 FEBRUARY 2019 | FUEL OIL NEWS | www . fueloilnews . com