3. 4. The circumferential chalk line on the hose next  to  the  coupling  has  been  drawn  before the hydrostatic test. The internal spring (if installed) is evenly spaced  and  flat  against  the  inner  liner. Ensure a gap exists between one of the end fittings  and  the  end  of  the  spring. Hydrostatic Test Upon completion of visual inspection, hydro- statically shop test the hose assembly with fresh water.  For  each  style  and  size  of  hose,  test  the pressure to ensure that it is twice the maximum allowable  pressure  shown  in  chapter  505  of  the NSTM.  When  you  test  pressure,  hold  for  not more  than  5  minutes  nor  less  than  60  seconds. When test pressure is reached, visually inspect the hose  assembly  for  the  following  defects: 1.  Leaks  or  signs  of  weakness 2.  Twisting  of  the  hose  (this  indicates  that some  twist  existed  before  pressure  was applied) 3.  Slippage  of  the  hose  out  of  the  coupling (a circumferential chalk line can help deter- mine this) If  any  of  these  defects  occur,  reject  the assembly. CAUTION Do not confuse hose elongation under pressure  with  coupling  slippage.  If  the chalk   line   returns   to   near   its   original position, no slippage has occurred and the assembly  is  satisfactory.  If  there  is  any doubt,  perform  a  second  test.  If  doubt persists  after  the  second  test,  reject  the assembly. Air Test Hose  assemblies  intended  for  gas  or  air service must also be tested with air or nitrogen at 100 psi and the assembly immersed in water. Random bubbles may appear over the hose and in  the  fitting  area  when  the  assembly  is  first pressurized.  Do  not  construe  this  as  a  defect. However,  if  the  bubbles  persist  in  forming  at  a steady rate at any particular point on the hose, reject the assembly. Installation of Flexible Hose Assemblies After completion of tests, proceed as follows: 1. 2. 3. 4. Install  as  soon  as  possible. Do not leave the hose assembly around on decks or on docks where they can be sub- jected  to  any  form  of  abuse. Make  up  hose  assemblies  as  late  as possible  during  the  availability  schedule  to minimize the chances of damage while the ship  is  being  overhauled. Install plastic dust caps, plugs, or tape ends to  protect  threaded  areas  until  the  hose assembly is installed. When   installing   flexible   base   connections, observe  the  following  requirements: 1. 2. 3. 4. 5. 6. Ensure  each  leg  of  hose  is  free  of  twist between  end  fittings. Ensure  the  fixed  piping  near  the  flexible configuration  is  properly  supported  so  that it  does  not  vibrate  from  the  resiliently mounted  equipment. Ensure the configurations are clear of all surrounding structures and remain so when resiliently   mounted   equipment   moves through  its  maximum  excursion  under shock. Locate   flexible   connections   as   close   as possible  to  the  sound-mounted  unit. Support  the  free  elbow  of  the  configura- tion  with  an  approved  pipe  hanger  so  as not  to  sag  or  otherwise  unduly  stress  or distort  the  configuration. Do not appreciably change the alignment of the hose configuration between the un- pressurized and pressurized conditions. If you  do,  you  could  cause  misalignment  or improper  support  at  the  fixed  end. 9-35