mbrooke
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What do they mean by "shall not apply" in regards to article 700? .........
Can you give us some context?
It means that those portions of article 700 specifically referenced do not apply to healthcare facilities. For example, 700.4 requires a generator to be sized for all of the connected loads to be operated simultaneously. NFPA 99, paragraph 6.7.1.2.7 states that the generator set(s) shall have capacity and rating to meet the maximum actual demand likely to be produced by the connected load of the essential electrical system.
Most of the requirements in NFPA 99 are also in NEC article 517. Paragraph 517.27 requires the life safety branch meet the requirements of Article 700, except as amended by Article 517. NFPA has also instructed the code making panel overseeing 517 that NFPA 99 is the governing standard for healthcare and that NFPA 70 should not contradict anything in NFPA 99. The most recent example I have is the selective coordination vs. coordination to 0.1 seconds discrepancy.
I think I've ran into this before too. You may be reffering to "700.10 D1 through D3 shall not apply. "
Does it mean the requirement does not apply? As in we are being less strict. You can ignore these requirements. That's the normal definition under of "shall not apply" used by NFPA.
But each paragraph lists a specific means of complying with the more general 700.10D. So does it mean that the specific means of complying listed in each paragraph shall not apply? IN other words, we are being more strict. You must find a better way to meet the more general requirement listed in 700.10D.
To make it more confusing, I'm not so sure they didn't really mean 700.10 D1.1 through D1.3 shall not apply. That would mean one must comply with either 700.10 D1.4 or 700.10 D1.5.
This whole idea of referring back and forth between 517, 700, and 99 yet deleting different requirements is getting a little crazy. Its even worse with the revisions every 3 years - as soon as they refer to one paragraph, it gets changed by another committee.
But NFPA 99 says article 700 does not apply?
For example, every switchboard and panelboard on the Life Safety branch requires a SPD because of the requirement in 700.8. The Life Safety branch on a single generator system also requires a portable generator connection box meeting the requirements of 700.3(F). This connection box is typically installed for the entire essential electrical system because it is easier and is more useful than just installing it for the Life Safety branch.
(2) 700.10(D)(1) through (3) - Requires feeder circuit, feeder-circuit equipment, and generator control wiring to be protected by sprinklers or be protected by a 2-hour fire rating, either through cable or raceway selection or concrete encasement. None of this applies. You can run the life safety feeders as THHN in EMT above a dropped ceiling that doesn't have the ceiling cavity sprinkled. A comment above 700.10 D1.4 and D1.5. These sections do not exist. I think there was some confusion and the correct references would be 700.10 (D)(1)(4) and (D)(1)(5). These would not apply since the parent 700.10(D)(1) does not apply.
Single generator in the electrical sense correct? I know of buildings with multiple gens, but only one dedicated to the life safety.
But I see many prints calls for concrete encasement of the life safety and protection of its branches.
Right. If you take down a generator for maintenance and the emergency egress lights would not illuminate upon loss of normal power, you need a way to connect another generator without modifying the permanent building wiring.
It could easily be a local amendment or how the different NFPA codes are adopted that leads to this requirement, but if you are going strictly by NFPA codes it would not be required. Job specs are certainly permitted to exceed the NFPA requirements. You could have an owner require all circuits be concrete encased. It wouldn't be wrong, but you would still shake your head and tell all of your friends about this crazy job that put all conduits in concrete.
That is an interesting approach. I probably would have tried to parallel the generators or have a tie breaker between the generator distribution equipment, but can see how the tiered transfer switch solution could work.
Do you have to program in delays in the transfer switches to keep all of the load from going to generator 2 upon loss of normal power with this arrangement? Do you have any issues getting the Life Safety and Critical branches up in 10 seconds?
My guess as to why some of the requirements were removed is that with all of the extra hospital requirements for testing, maintenance, inspections, etc., there may be little practical benefit for the added construction costs. That got me thinking about the actual prevalence of hospital fires, and led me to this site: https://www.usfa.fema.gov/data/statistics/reports/snapshot_hospital.html
Some interesting facts on US hospital fires from 2012-2014:
1. Only 3% of fires extended beyond the room of origin.
2. 68.5% of fires were from cooking.
3. 60% of confined fires (44.5% of all fires) were confined to a cooking vessel.
A lot of this comes from the way we viewed the sick I think...
I would blame the dollars more. When a power outage can cost you millions of dollars per hour or per minute, the ROI on some insanely robust electrical distribution systems looks pretty attractive. Easy to quantify, easy to fund, easy to build.
When most of your revenue is based on CMS reimbursements and subject to the whims of the federal government, it may be a bit more difficult to defend spending money beyond what is required. There are quite a few hospitals, especially in more rural areas, that are living on pretty thin margins.
Not that I am arguing against protecting the feeders, but it is a design decision that exceeds the NFPA requirements. Also, protecting the feeders would not have helped any of the cases you noted above. Again pure speculation here, but I still think that the incidences where protecting the feeders in a hospital would have mitigated or prevented an actual adverse outcome must be fairly rare. Otherwise I think it would be easy to provide justification to the code making panels to get those changes included.