What is the Purpose and Difference in Equipment Schedules and Specs

[engineerheriam]

For an MEP type job, what is the purpose of Schedules?
I understand that the specs are a detailed description and listing of what the installer will bid on.

So what is the Equipment Schedule used for?

Are they the same thing? If not, what is the difference?

 

[MintJulep]

In a black and white world:

A schedule is a list of specific equipment that you want provided.

A specification is (or could (or should) be) a description of the performance you want. It is then up to the bidder to select the appropriate equipment to achieve that performance.

In the real world, most "specs" are a combination of the two.

 

[engineerheriam]

so should the bidder follow the spec (several pages long and very detailed) or should the bidder follow the single page equipment schedule?

if the equipment schedule serves as the basis to select equipment, then what is the full spec for?

 

[GMcD]

The equipment schedule is the basis upon which the drawings have been coordinated, and drawn around specific brands of equipment. In the MEP world, there really are no true "equal products", since the manufacturers of various MEP equipment all make their own little flavours of equipment that can provide similar performance, but typically have different dimensions, weights, maintenance clearances, etc.

The Equipment Schedule specifies the specific preferred brand of equipment that meets the design intent (the designers favorite brands, usually).

The detailed Specifications include detailed minimum performance standards and installation (execution) requirements to allow the Contractors to supply different brands of equipment, provided they can meet the minimum specified performance and installation standards.

A Trane 200 ton air cooled chiller, an Airstack 200 ton chiller, and a York 200 ton air cooled chiller are so dissimilar that they really aren't "equal" at all, and they all have different installation requirements, and different performance issues. Hence the "detailed performance specs" to allow the Contractor to try to use different brands of equipment, but still meeting certain operating and design criteria that are deemed important for that particular project and Client - pressure drops, flows, delta T's, refrigerant type, compressor type, kw/ton, etc.

 

[marcoh]

On the project I am working on currently we just issued the specification and technical schedules.

As an example there are around 80 ventilation fans in the project, the specification gives the technical requirements for each type of fan, the schedules schedule the duty and specific requirement for each fan, eg air flow, pressure, efficiency, motor size diameter, noise levels etc.

For items such as chillers, there typically only a few different ones in a project, and could just as easily be specified with or without schedules. If there numerous items of a type of equipment, such as VAV boxes, fans, pumps, AHU's, etc it becomes simpler to schedule all the duties of the equipment.

I view the technical schedules as part of the specification (or appendix A in all my specifications). The design documentation includes all drawings, and specifications, and schedules and all need to be read in conjunction with each other.

 

[willard3]

The bidder is responsible for the contracted work which includes both the schedules and the specification.

Some clients like schedules because the technical information stays with the drawing set....most clients throw out the spec after the project has been accepted.

 

[GMcD]

Willard3: It's also my experience that the Contractors don't even read the spec until there's a problem, or it gets spotted during a site review that they've deviated from the specifications standards. Then it's a fight to enforce the quality control and execution requirements.

I also often find that suppliers who propose equipment other than the specific make and model as scheduled don't read the specs for a lot of the detailed performance and installation standards, and we get crap submitted for "approval" and then we get the hostility when we reject stuff that clearly doesn't meet the requirements.

 

[sridhar1312]

schedule is the bill of quantity and does not cover the specific details of the equipment /materials.
Detailed specifications details gives the specific requirement of materials that is required in materials /equipments.

Every equipment may meet all the technical requirement or more, some times some of the equipments may not meet all the specification need.
Schedule of quantity is always in conjunction with specifications.

 

[CountOlaf]

I personally like to have all the material type information and references to standards/codes etc in the "written" specifications, but leave all the numerical/engineering stuff on the tablulated schedules. Schedules on the drawings are very helpful to the "next" engineer trying to meake heads or tails of an existing system. Good luck trying to find the specifications 30 yrs later. At a former company I worked at, we didn't include schedules unless there was more than one of a particular type of item, but I always provide a schedule even if there is only one for the aforementioned reasons. There certainly can be some overlapping information on the written specifications and equipment schedules. I guess it's kind of like the debate as to whether to have a note with a leader line vs a listing of key notes. I usually go to key notes when the leader line note needs more than a sentence...just preference I guess.

 

[HVAC68]

Typically, "Schedule" furnishes details such as capacity, operating parameters, etc - Cooling capacity, flow rate, temperatures, acceptable maximum power drawn, maximum weights, maximum dimensions, maximum pressure drops, static pressures, type of equipment (screw chiller, backward curved centrifugal fan, inducted draft cooling tower, etc., etc.) - i.e. the basis on which the designer has worked on the project - more of a "performance specifications". This is, needless to say, changed from project to project, depending on the specific requirement of the project.

The specifications, on the other hand, are more general in nature covering the constructional features, testing requirements, relation to codes, standards, etc. These are, typically done once and rarely modified (modified only when there are major technological advances) and forms part and parcel of the consulting engineer's standard documentation.

HVAC68

 

[ChrisConley]

Schedules are used when more than one capacity, or size of equipment is specified for a given specification. A specification for a single piece of equipment can be done with the capacities, etc, included in the specification. If there are multiple units then a schedule is used to differentiate the differences between them.

A simple example is a fan schedule. You would have one specification section for each type of fan, and then a fan schedule outlining the different capacities.

 

[marcoh]

"I also often find that suppliers who propose equipment other than the specific make and model as scheduled don't read the specs for a lot of the detailed performance and installation standards, and we get crap submitted for "approval" and then we get the hostility when we reject stuff that clearly doesn't meet the requirements."

It called profit maximisation for the contractor and you need to realise your design is only one of the many options that could be installed! On a recent project, the contractor refused to install something because it was too expensive, typical consultant over-design, and not required, all of this despite it being clearly specified, scheduled, and a specific client request.

 

[mauricestoker]

Schedule is used quite often for basis of design, not just for salient characteristics, but to also identify at least one model that will fit in the available space. Least that's one of my uses, as I have had many problems on renovations where a unit is specified but will not fit. Schedule or specifications do not address spacce by themselves, but having an identified model that will fit has resolved some ugly claims.

 

[GMcD]

Marcoh: Oh, I know it's "profit maximization" by the Contractor, so what? This is contract law 101 - the specification forms part of the Contract Documents, and if the Contractor chooses to supply something that doesn't conform to the Contract Documents, then it's his problem, not mine. As the Engineer of Record, my duty is to the Client, and non-conforming equipment or installations are not acceptable, unless the Client chooses to take a cost saving for the different equipment. And we all know that whatever "cost saving" might be offered by the Contractor will be pennies on the dollar of the actual cost saving (I can use a telephone to check with suppliers,too).

At that point I make sure that my advice and recommendations are recorded and filed, and that has helped me a number of times when the costs savings and system or equipment performance have failed to live up to the suppliers' or Contractors' claims of "it's equal or better" than what was specified.

That being said, these days there is far too much reliance on "master specifications" that are edited by people who don't know enough, resulting in over-specification or completely wrong material contained in the body of the spec, that doesn't even match the scheduled equipment. If the checking isn't good enough, crap will slip through from the engineer's end too. Unfortunately, these days building services engineering is seen as a commodity service, and it's a race to the bottom for fees, service, and quality.

 

[HVAC68]

Further to the last paragraph of what GMcD has written - there are many occasions (too many for comfort, these days), wherein the designer or consulting engineer doesn't know what he is doing and ends up overdesigning systems and/or selects wrong type of system itself. As long as such instances are exceptions than a regular feature, it's OK. But, these instances are rising by the day. This results in the Contractor using his "design" knowledge and experience and uses what is popularly known as "Value Engineering". The revised schedule or sometimes even the scheme ends up being cheaper than the original proposal. Obviously, the Contractor on his part will pass on only with a part of the savings, as he has carried out some amount of work and needs to get paid. At the end of the day, it becomes a "win-win" situation, more often than not.

The customer pays lesser than his original budget and the contractor makes more money than the original !!!

The key is to have good and knowledgeable consultants who know their job !

HVAC68

 

[willard3]

snip
>>the specifications, on the other hand, are more general in nature
snip

Specific and general are antonymic. I have heard this argument a lot in arbitration.....there is no such thing as a general specification. Specifications are specific.

 

[mauricestoker]

There are general specifications, and that is recognized (Division 0 and 1). First specification of each division is usually general. Beyond that, if it is not specific, I can't see why it would be in a specification. Not an etymologist, but "specify", "specific" and "specification" would seem to have the same root.