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Recent content by mflam

  1. mflam

    HDPE double wall pipe for sewage applications

    It just came to my attention that there is now available on the market a double walled HDPE pipe with a water tight bell and spigot joint, large diameters for sewage applications. Anyone have experience with it that they would like to share?
  2. mflam

    Emergency Generators for Pump Stations

    I want to put hard wired emergency generators at wastewater several wastewater pump stations. The problem is that the industrial grade generators are too big. For example, a seven lot subdivision, pump station has two 5 hp pumps and they never both run at the same time. The actual KW that I need...
  3. mflam

    Pump Operation Standby Cycles

    I'm going to ask this question a couple ways. In a wastewater pump station, how long should a standby or spare pump be allowed to stand without operating? Or, at what interval should should the lead-lag pumps be switched?
  4. mflam

    Cleaning Pressure Sewer Hydraulically

    We have a 24 inch diam force main on a waste water pump station. The length of the pressure line is 5,800 lf. In profile the line has two low points before discharge to a chamber. Gravity flow takes over. From the point of discharge to the most distant low point is 2,200 lf. There is evidence...
  5. mflam

    Reversing Direction of Flow in Water Main

    We are planning a water project in an urban setting. We will be taking a section of a large water main out of service. The temporary water service will result in the direction of flow in some streets being reversed. What are the risks? How can this be assessed in advance? What can be done to...
  6. mflam

    tapping sleeves vs tees

    Thanks, guys. Dick, you are so correct about the "finesse" issue. Trouble is, I'm not out there in the middle of the night in January when there is a break. I will keep nagging on this. Your input is most useful for the conversation that we are having here.
  7. mflam

    tapping sleeves vs tees

    I read a 2007 post on this subject. Following up. For now, I'm going to define a tapping sleeve as the stainless steel device and a tapping tee as a DI device with MJ gland to make the seal around the pipe. My water crew insists that the DI tapping tees are the only thing they want used. Their...
  8. mflam

    Tank Wall Penetrations

    Thanks, everyone for your input. I'm going to go ahead with the bulkhead fitting. The risk to the cable is the deciding factor. If we get a little ice in the tank and the water level changes, it will rip the cable. We'll be draining the tank to install the mixers so now is the time to drill...
  9. mflam

    Tank Wall Penetrations

    What do you think? We are going to install a low-voltage mixer (48 VDC) in a 2 MG water standpipe, 60 ft diameter 110 feet high. I can either loop the power cable all the way up to the roof of the tank and down, or I can drill through the 1 3/8 inch thick plate and intall a water tight fitting...
  10. mflam

    Sizing Rip-Rap apron at Blow-off

    How much space do you have? That's a lot of water. I don't know of any calculation that would support this but, I suggest you use the biggest rip rap available. In the northeast, it is commonly called "crusher run." Also, you'd better be aware of where the water is headed, even after you have...
  11. mflam

    Valve Actuator Materials

    It has come to my attention that some newer valve actuators are made of fiber reinforced polyester or other plastics. I'm looking at hydraulic cylinder linear actuators in particular. Any comments on how they perform and hold up?
  12. mflam

    Flexible couplings in water piping

    We are replacing a 12 inch water main in a city street with cement lined ductile iron pipe. We will be stopping about 30 feet away from a highway overpass where the main is hung below the bridge. The plan calls for finding the existing main, cutting it and coupling to it with a solid sleeve...
  13. mflam

    Temporary Water Main and Cross Connections

    Should an above ground temporary water main be considered a potential source of contamination? Should it be isolated from the permanent system with backflow preventers? What if it is looped into the permanent system at two points? The loop configuration makes the system more robust and...
  14. mflam

    Immersion Heater to Prevent Water Service Freezing

    I ran the following post a few years ago. Since 2005, does anyone have any further comment? Question: Has anyone had experience using wire-type heating elements directly inserted into water supply piping to prevent freezing? Anyone experienced adverse effects on the quality of the water...
  15. mflam

    Standards for Toilets

    We have recently moved into a new building. A gentleman in the office has asked if new toilets in public buildings have a minimum clearance from the seat to the level of standing water in the bowl? (This is a serious question and I only wish it was mine.)
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