Surveying 2 – Taking a level reading – OTEN Building & Construction

Surveying 2 – Taking a level reading – OTEN Building & Construction

♪ (upbeat music throughout) ♪ We’re at Nirimba College
with OTEN Head Teacher, Dave. What are you going to be showing us next? Jason, I’m going
to introduce you to the staff and how to take a reading to it
from the instrument we’ve just levelled. This is normally
a two-man process on site. Would you like to give me a hand? Love to, bring it on! Jason, I now just want to show you
some features of the staff. If you could just lower
that down for me… This staff is a five-stage staff, so it has five sections to it. And you’ll notice, if you wouldn’t mind
extending that out now, as you raise it up, it actually needs
to clip in here at the back, and that clip is on each section
of the staff. Also, you’ll notice that the first section
is in black, second section is red, it alternates up the staff, so that the person
looking through the instrument can see that we’ve actually extended, in this case, the first
and the second section. So, that’s just to check to make sure
that we’ve extended the staff properly. Second thing is,
this is an aluminium staff. If we were working
near overhead power cables, it would be advisable that we were using
a fibreglass staff, just in case we did contact
those overhead wires. Next, this staff is graduated
in what we call an ‘E pattern’. And on building sites, we tend to take a lot of measurements
with this measuring tape. The tape is graduated to millimetres and that is generally the order
of accuracy that we expect on most… activities on site. No different to reading levels. We actually take levels in metres, but to three decimal places. So, we’re getting down to the millimetre. Unfortunately, the staff is only graduated
to 10 millimetre sections. If we place the measuring tape
on the staff, we can see that, for instance,
here that line there is actually 800 millimetres,
or 0.800 metres. These 10 millimetre blocks mean
that is a reading of 0.810, 0.820, 0.830, 0.840, 0.850, -60, -70, -80 -90,
till they get to 0.900. I’ve said we need to read
to the third decimal place, so we actually need to interpolate,
in other words, estimate, at what section, or what millimetres
we are reading, when we’re in one of these
ten millimetre blocks. If we’re in the middle, that’s quite easy. If we’re in the middle of that section, that would be 0.8, 0.85, 0.855. Okay Jason, let’s go take a reading, but before we do, I’ll just make you
aware of a couple of things. First off, I need you to make sure
the bottom of the staff is clean, so that I’m getting an accurate reading. Secondly, when you’re holding the staff,
that’s lovely, keep your hands clear of the place of the staff,
so I can see all the graduations, and thirdly, I’m going to get you
to wave the staff, rock it just forward and back of vertical. I will know when you’re
in the vertical position, that will be my lowest reading. Because when you lay back,
or lay forward, my crosshair will give me
a higher reading on the staff. You may not be holding it
in the vertical position if you just hold it like that, and I can’t tell if you’re leaning forward
or leaning back, so by slowly waving the staff, I will know the lowest reading
is the one I’m after. Now we’re going to take a reading
to the staff. Jason’s placed the staff on a peg
that I want to get the level of, so I’m going to look through the telescope
and obtain that reading. Jason’s going to wave that staff
a little bit for me. And I will know the lowest reading
is the one I’m after. And my reading is… 1.372. So, I’d just like to show you now
where that reading is on the staff. It’s about there on the staff. 1.3… 1, 2, 3, 4, 5, 6, 7… and two millimetres. 1.372. So, what we’ve just seen here
is the order of accuracy, the staff graduation, how to hold a staff, and how to take a reading. What are we going to see next? Jason, next time I’m going to show you
how to complete a two-peg test to check that the level’s
giving us accurate readings.

Comments (30)

  1. thnk u vry mch for these videos.

  2. thanks for uploading very help full

  3. great work, guys!!!

  4. Guys, great job making these videos. Great review for my students. Thanks.

  5. thanks…………………

  6. good job thnkx sir

  7. Why are you after the lowest reading? I don't understand? Generally you want to hold a rod plum? What kind of surveying is this?

  8. Thank You very much, this has been more help than you could ever imagne.

  9. Jasons waving needs work……

    It's hard to get the staff.

  10. sorry but the staff guy holding staff during u read or take the reading is wrong because staff man always stand straight and he will keep the staff in between feet and staff must b touch to his nose

  11. you are very good and you teach very well but we request you to make your explanation with subtitles to understand every person who needs it thank you for your helping

  12. Hey, Great Video, just one thing you forgot to include is the additional equipment that comes the instruments E.G (Vial Level); for those who might not be familiar with the name it is a device that clips onto the staff at the back like a clip on version of the bubble found on the Leveling Instrument which is used to aid the process of centering the leveling machine as shown in previous tutorial, it help the person holding the staff to always ensure a reading is more accurate by leveling the staff bubble…

  13. I like your information about levelling..,



  16. That's why aussies put 0 on the end of everyone's name aye. 0.80, 0.810, Shaneo, Daveo and Jono.

  17. Well understand, i like surveying and it is one of my profession skills. Thank you sir.

  18. ямар гоё аашгүй багш вэээ

  19. I have been searching for such a video. I am happy that finally i have seen what i have been looking for.

  20. Wave the staff back and forth? I’ve never heard such bullshit in all my life

  21. How did Dave read the staff while it was still waving?

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