I'll pass these specs along. I appreciate your comments about negotiation with the colo provider...but seeing as I *am* the colo provider, my perspective is that there is very little window for negotiation... Either I provide your spec or I don't. I haven't found it difficult to meet specifications such as these and enter into SLA for them. I expect all of you to hit me pretty hard on these sorts of things, so the more input now the better. -J
Donelan's Climate Settings: 8,500 BTU/hr heat dissipation per full rack Not all of it must be installed on day 1, but I want to see pre-planning how the HVAC will be expanded to meet the load (e.g. enough room reserved, aisles wide enough, to bring in additional units later, pre-plumbed for the outside heat exchangers, compressors, etc). Minimum 1 air change per hour This is actually a 'clue-check' question. How the co-locate operator answers it will tell you if they really know their HVAC systems. Unoccupied areas can get by with as little as 1 air change per 24 hours, but if you are doing an install or other work in the area, you'll appreciate more frequent air changes. Humidity: 35% to 50% R.H., non-condensing, max 2% change per hour Ideal: 40%-45% R.H., measured at three locations with max 5% variation. Humidity is expensive to control, so it is common to have R.H. at the high end of the range (e.g. 45% R.H.) in areas naturally more humid (e.g. northeast) and R.H. at the low end of the range (e.g. 40% R.H.) in areas naturally drier (e.g. southwest). Maximum (not to exceed 24 hours/annually): 20%-60% R.H., non-condensing Temperature: 59f to 77f (15c to 25c), max 4f (2c) change per hour Ideal: 72f (22c) at my rack, but since it is econmically infeasible to control the temperature at the rack level, I normally ask for 68f (20c) as a room average, measured at three different points, with a maximum of 4f(2c) variation. The assumption is at worst I'll end up with 72f(22c) at my rack. Anything much colder than 68f(20c) is a bit harsh on humans that need to work in the area. A tech thinking about how cold he is, isn't thinking carefully enough about the job he is supposed to be doing. Maximum (not to exceed 24 hours/annually): 49f(10c) to 85f(30c)
You'll notice I tend to be metric-centric in my measurements. These are much stricter than your typical C.O. environments.
Its more a practical matter of negotiating with the co-locate operator, and asking for more than you really need on the assumption even if they deliver just 50% of what they promise it won't be an immediate disaster. They may have no problem delivering 68f(20c) when the co-locate is 90% empty. But when it fills up, I'm betting with the lower the starting point, the less likely I'll run into my upper limit.
I choose most of the values to give myself enough of a buffer before exceeding any equipment parameters, so I can try to negotiate a resolution with the co-locate operator before the levels start to causing equipment to shutdown. Otherwise if you set the limits at the maximum your equipment will tolerate, a co-locate operator may not do anything until after the temperature goes over 104f(40c), but by then its too late. Obviously the co-locate operator wants to write the contract with the largest acceptable environmental ranges possible, and the co-locate lessee wants the narrowest acceptable environmental ranges. Its a barginning point, how much do you really want to pay for +- 1 degree, or +- 10 degrees.
In reality, most modern electronic equipment will operate well in a wide range of human-habitable enviroments, as long as the enviroment is stable. Its the oscillations that will kill your equipment every time. And in most cases, if the price is the same, I am willing to trade a particular value for tighter tolerances, e.g. 75f+-1f. But the price is rarely the same, so I generally choose the bigger range as shown above. -- Sean Donelan, Data Research Associates, Inc, St. Louis, MO Affiliation given for identification not representation
--- [ Jay Adelson adelson@equinix.com ] [ Chief Technology Officer Work: +1-650-813-9031 ] [ EQUINIX, Inc., Palo Alto, CA Fax: +1-650-858-8368 ]