Questions tagged [specifications]
20 questions
6
votes
2 answers
Tube Steel - ASTM A1085 vs. A500
Recently, tube steel manufacturers in the US have begun using the new ASTM A1085 specification for forming tube steel (a.k.a. hollow structural section or HSS) shapes, as opposed to the existing A500 specification.
From what I've read (here and…
grfrazee
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4
votes
2 answers
Inert gas use during HVAC line installation
When brazing HVAC linesets, the correct method is to flow an inert gas through the line in order to prevent interior oxidation of the copper and brazing products. However, as a specifier, I can say that this needs to be done until I'm blue in the…
Secundus
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3
votes
1 answer
Industry standard for AC wall electrical box space
Are there any industry standards (Engineering Specifications) for the minimum / maximum space required for the electrical box that holds a regular AC wall plug?
The problem I am trying to solve is quite simple - are / is there any local (USA,…
KingsInnerSoul
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3
votes
2 answers
Specification of linear speed dampers
I'm looking at linear compression dampers and finding them most commonly specified only with a "Max Force" – e.g., 270 lbs.
However, since the damping mechanism is provided by hydraulic or pneumatic resistance, the damping force must be a function…
feetwet
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What is meant by "accuracy within factor of 2" in sensors?
I've spent quite some time googling the meaning of "factor of (number)" in sensor accuracy but could not find any document explaining the meaning of this expression used to describe sensor accuracy. Specifically, I'm looking for the meaning of…
Jim
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2
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Moment Of Inertia Specifications AISC
Is there some regulatory body/inspection that verifies the AISC specified Moment(s) of Inertia for steel I-Beams? So for example, if a mill produces a W8x21 and says hey, it meets the specs, it's 8 in Deep and is 21 lbs/ft, and because I say so, it…
Andyz Smith
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How to find building specs & blueprint(s) for an apartment complex?
For any given apartment complex in the U.S. (if you want to get specific, I am wondering about NYC), how does one track down the building's specifications. I'm talking about specs as detailed as the thickness of the walls (this is really the detail…
user110391
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Are there any specifications that address the environmental conditions items traveling though international post should be able to tolerate?
In terms of temperature extremes, air pressure, humidity, shock, ... In determining what ranges to design for in a device are there any standards or at least guidelines either by postal services or governmental departments that can be used to gauge…
norlesh
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1
vote
1 answer
buying a mounted bearing determining radial vs axial load it can bear
Can anyone tell if these bearings load ratings are for a radial load or an axial load ?
Bearing designed for an axial load is (sometimes?) called a "thrust bearing".
Based on its mounting, I guess this is a thrust bearing for an axial…
kinidkinid
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1
vote
0 answers
How to specify plumbing fixtures so models are not immediately out of date
Rock-solid guide specifications are the ultimate pipe-dream of consulting engineers because they minimize the amount of time that needs to be repeatedly spent on the minutiae of tiny details from project to project.
In specifications for items that…
Secundus
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1
vote
0 answers
External Static Pressure on Open Gallery Fan
I routinely work on building designs that incorporate rooftop upblast fans over large industrial spaces such as this one:
When selecting these fans, as with every other fan, you need to determine the external static pressure that the fan will…
Secundus
- 561
- 3
- 19
1
vote
1 answer
Comparing 2 shock scenarios with different magnitudes and times
For example,
How does one compare 100 g's for 6 milliseconds to 45 g's for 11 milliseconds. These are two different shock scenarios with different magnitudes and times, so how can I compare them? If I have something that is shock rated at 100 g's…
Mike James Johnson
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0
votes
2 answers
What are the Exact Rules for Significant Figures, Precision, and Uncertainty?
In the physical sciences (which are physics, chemistry, astronomy, materials science, etc.), we learned that the uncertainty is +/- the smallest unit (which is 1) of the last significant figure if the uncertainty is not given in a recording of data.…
0
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4 answers
Product idea then specification, or specification then product?
I am trying to write a requirements specification for a new product but I am confused about where I should start. Do you start with the product like "A new kettle" and proceed from there, or do you start with nothing but the current problem for…
Richard Bamford
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0
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2 answers
What's the process with requirements and design?
What is the usual way which requirements are managed and made sure to be fulfilled in designs? Sorry if the question is vauge and overly general but i'm just looking for a crude description.
Thanks
Richard Bamford
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