AS seismic and wind design 1

[rbel038]

Hello all,

We design pressure vessels to ASME Div.1 usually and have in the past had our AS1210 expert designer to prepare the designs to meet AS1210 criterion as well.

Ive had experience applying other standards for wind action and seismic action , but im unsure as to how to go about this regarding our vessels travelling to australia.

At the present time we have 5 travelling to queensland with AS4343 Haz level "B" , so they will be verified and registered. What i dont understand is if there is any clear OSH or dept. of labour rules regarding what loadings must be considered and when.

I have had a look through the queensland regulation site but cant find anything specific to plant design and sesimic / wind loading.

To summarise im looking for minimum criteria to apply wind / seismic design to the vessels. or is it rather an exercise in using judgement?

Thanks

 

[hokie66]

AS1170 is the Australian standard for loading. It consists of 5 parts. Wind is covered in AS1170 Part 2, and seismic in AS1170 Part 4. A Queensland structural engineer would be able to assist.

 

[rbel038]

My bad hokie i was not very clear in my original post. We have AS1170 and have used it in the past (myself with wind design of a vent stack. The issue is not with the design using AS1170 but rather when it must be applied to a pressure vessel (something like centre of gravity X meters above ground).

What i have found so far is that it is not applicable to importance 1 structures. I now have to investigate whether pressure equipment at a remote site can be classified as this.

I think i will take up your advice and seek a local PE in queensland.

Cheers

 

[bernoullies123]

As you may of realized while doing your research, Queensland legilation rarely stimpulates the Australia Standard that must be used to satisfy the requirements of the particular legislation. In regards to AS/NZS 1170, you have noticed that it is not called up any legislation using the search tool.

Generally, most requirements are contained under a motherhood legislation. Generally everything in regards to engineering will fall under 1 peice of legistlation which is the Workplace Health and Safety Act 1995.

Depending on your circumstances (designer, manufactuerer, supplier etc.), your obligations under the Act is defined in Part 3. Great, so what does that mean? There is a guide specific to s30B which provides some good info in regards to ones obligations, and can also be used as a guide for any other section of Part 3: Guide to the workplace health and safety obligations of designers of structures

http://www.deir.qld.gov.au/workplace/resources/pdfs/designersobligations.pdf

Pressure vessels need to be designed for their anticipated loads. There is both wind and earthquakes in Australia, therefore these need to be addressed. To satisfy your safe design obligations under the Act, these need to be accounted for, and if done to the Building Code of Australia (BCA) and/or Australian Stardards (i.e. AS/NZS 1170) then you would probably satisfy your obligations under the Act.

Now you have got to the AS/NZS 1170, and need to determine the importance level. As per AS/NZS 1170.0:2002 2.2(a)(i) you need to refer to the BCA. Table B1.2a (2009) has 4 levels which are basically the same as the first 4 levels in AS/NZS 1170.0 Table 3.1 which is applicable to New Zealand. Pressure vessel with a Hazard level of B per AS 4343 is classified as Medium Hazard, therefore importance level 1 of low hazard is not applicable, therefore leaves for levels 2 to 4. As you have guessed, the level is based on judgement, but the guide noted above provides info on how to approach this in a generic sense and not specifically to importance levels.

With the above said, you are not alone, as your there any many others who are also responsible, therefore they too also have obligations to define and agree on most of these factors.

Just as important to the pressure vessel, is the actual support/foundation of which it will be resting on. These will also have to be designed (by the structural engineer) while considering all the applicable loading cases of which the wind and earthquake from the PV will also need to be considered. This is important as the same factors (importance levels, wind speeds, acceleration) need to be consistent between the 2 designs (1 or PV, 1 for structure). No good having just 1... i.e. earthquake comes and the vessels survives but is located elsewhere as the support structure didn’t.

 

[bernoullies123]

As you may of realized while doing your research, Queensland legislation rarely stimulates the Australia Standard that must be used to satisfy the requirements of the particular legislation. In regards to AS/NZS 1170, you have noticed that it is not called up any legislation using the search tool.

Generally, most requirements are contained under a motherhood legislation. Generally everything in regards to engineering will fall under 1 piece of legislation which is the Workplace Health and Safety Act 1995.

Depending on your circumstances (designer, manufacturer, supplier etc.), your obligations under the Act is defined in Part 3. Great, so what does that mean? There is a guide specific to s30B which provides some good info in regards to ones obligations, and can also be used as a guide for any other section of Part 3: Guide to the workplace health and safety obligations of designers of structures

http://www.deir.qld.gov.au/workplace/resources/pdfs/designersobligations.pdf

Pressure vessels need to be designed for their anticipated loads. There is both wind and earthquakes in Australia, therefore these need to be addressed. To satisfy your safe design obligations under the Act, these need to be accounted for, and if done to the Building Code of Australia (BCA) and/or Australian Standards (i.e. AS/NZS 1170) then you would probably satisfy your obligations under the Act.

Now you have got to the AS/NZS 1170, and need to determine the importance level. As per AS/NZS 1170.0:2002 2.2(a)(i) you need to refer to the BCA. Table B1.2a (2009) has 4 levels which are basically the same as the first 4 levels in AS/NZS 1170.0 Table 3.1 which is applicable to New Zealand. Pressure vessel with a Hazard level of B per AS 4343 is classified as Medium Hazard, therefore importance level 1 of low hazard is not applicable, therefore leaves for levels 2 to 4. As you have guessed, the level is based on judgement, but the guide noted above provides info on how to approach this in a generic sense and not specifically to importance levels.

With the above said, you are not alone, as your there any many others who are also responsible, therefore they too also have obligations to define and agree on most of these factors.

Just as important to the pressure vessel, is the actual support/foundation of which it will be resting on. These will also have to be designed (by the structural engineer) while considering all the applicable loading cases of which the wind and earthquake from the PV will also need to be considered. This is important as the same factors (importance levels, wind speeds, acceleration) need to be consistent between the 2 designs (1 or PV, 1 for structure). No good having just 1... i.e. earthquake comes and the vessels survives but is located elsewhere as the support structure didn’t.

 

[gr2vessels]

I'm assuming that you are using PV Elite or similar for your design;- I also assume you know that the PV Elite allows you to select the AS 1170 code for wind and seismic design. I assume the Compress does the same.

The AS 1170 design is based on the data selected for the actual location of the vessel (seismeic and wind data). The standard(s) will provide you with the basic data for your design, but detailed data can be sourced from the project design basis or from the purchaser. If you intend to do a separate structural design for your external wind and seismic loads, you'll be better off calling in a Queenslan PE for those calcs and then you add those loads to your PV calculations (I wouldn't do that, I'd rather ask a PV Elite designer for help).
Cheers,
gr2vessels

 

[rbel038]

Hi all,

As a follow-up for anyone else looking for information in this area i suggest having a dig through AS1210 - Appendix J.

It spells out there how the other structural codes (AS1170.X) translate to pressure vessel design under AS1210. And modifies them from 'limit state' design to 'permissible stresses' which is rather important.

It also points out that no seismic design is warranted for a vessel with a service weight under 1000kg.