I need to design the roof structure for a sports facility. I have no information with regard to HVAC design at this stage. Also, the HVAC may change in future. Thus I don't know what load to apply to the structure. I intend to give the HVAC and electrical engineers a weight envelope in which they can operate.

Is there a standardised list available which would give an indication of what loads I can assume for this?

  • 2
    $\begingroup$ It is likely addressed in a code or standard - what country are you practicing in? $\endgroup$ – Ethan48 Nov 16 '15 at 15:50
  • 1
    $\begingroup$ I am currently in Namibia, and we are free to use the South African Standard, which is now based on Eurocode, or Eurocode directly. $\endgroup$ – NamSandStorm Nov 17 '15 at 13:02
  • $\begingroup$ Terrific. I'm only familiar with American codes, but we have some members who work with eurocode, so hopefully they will have some insight. $\endgroup$ – Ethan48 Nov 17 '15 at 14:19
  • $\begingroup$ Thank you Ethan48, loads are loads, so it should not matter which code has the information. If the American codes have a section dedicated to my scenario. $\endgroup$ – NamSandStorm Nov 18 '15 at 6:43
  • $\begingroup$ A bit of googling: the best advice I can find is 4psf over the entire roof, plus allow 1000lb as a concentrated load somewhere. 1000lb seems high compared to other results, 500lb seems more normal, but of course it massively depends on how big the building is. Apologies for it not being codified values; hence comment rather than answer. $\endgroup$ – AndyT Nov 18 '15 at 15:58

I don't think what you are looking for really exists, in terms of a standardized list of HVAC/services loadings. Building codes don't usually specify dead loads, probably because they are, in principal, known. Typically only imposed (live) loads are specified. From the buildings I have worked on the services loadings were essentially copied from similar buildings/agreed with the HVAC contractor. There are some generic guidelines available. For example:

The Structural Engineers Pocketbook uses 0.15 kPa for ceiling and services

The Arup Structural Scheme Design Guide has 0.25 kPa nominal and 0.4 kPa for HVAC (I only have an old version so don't know if that has changed...)

The Steel Construction.info site (which is a pretty good resource) has 0.25 kPa as being a typical services loading.

ASCE 7-10 in Table C3-1 lists a dead load of 4 psf as a minimum 'mechanical duct allowance'. Which is likely where the 4 psf (0.19 kPa) mentioned in the comments originally came from and is consistent with the above references.

The Designing Buildings Wiki has 0.85 kPa for Raised floors, ceiling and building services equipment combined.

Hard to say if these would be applicable to your situation. Also you would need to deal with heavy equipment (condensers, fans, heaters, etc) which are not considered in these loadings.

The HVAC contractors tend to want to put holes all over your structure as well, so it would probably save time and money to consult with them early in the design and sort out what they need.

| improve this answer | |
  • $\begingroup$ This is as close to a perfect answer I could have hoped for. Thank you so much. $\endgroup$ – NamSandStorm Nov 19 '15 at 19:51

In my experience, appealing to codes that may or may not have been intended for your specific application is a costly business practice. There is no guarantee a load rating will be sufficient for the variables involved.

If I were in your situation, I would contact the intended HVAC company or another prominent HVAC company in you area. Take one or two of the engineers out to lunch and ask them to review your design as a colleague. They will immediately be able to see the red flags, be able to give you a model number for the largest possible air handler for that size building, know the capability of cranes in your area, and will be 100% familiar with the codes in your area. They will be glad to help because in a couple months they will need to ask you a roof structure question for one of their unrelated projects.

Even if you do find the exact code specification you are looking for I would encourage you to reach out for those kind of connections to experts in your community.

| improve this answer | |
  • $\begingroup$ This is not quite how it is going to work. Most engineers have different approaches, tying myself down to one will not work. Someone somewhere must have researched this properly. $\endgroup$ – NamSandStorm Nov 19 '15 at 5:45
  • 1
    $\begingroup$ Im sure its in there somewhere. Good luck. law.resource.org/pub/us/code/ibr/icc.ibc.2009.pdf $\endgroup$ – ericnutsch Nov 19 '15 at 6:16
  • $\begingroup$ Thank you Eric. It would have been nice to know in advance what I am downloading and where to look, though. $\endgroup$ – NamSandStorm Nov 19 '15 at 11:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.