Ventilation rate reduction

In addition, they are usually constructed without isolation valves on the fuel supply lines. As a result the final connection in the pipework cannot be leak-tested. In practice, it is tested as far as possible at the manufacturer s works but often not leak-tested on-site. Reference 32 reviews the fuel leaks that have occurred, including a major explosion at a CCGT plant in England in 1996 due to the explosion of a leak of naphtha from a pipe joint. One man was seriously injured, and a 600-m chamber was lifted off its foundations. The reference also reviews the precautions that should be taken. They include. selecting a site where noise reduction is not required or can be achieved w ithout enclosure. If enclosure is essential, then a high ventilation rate is needed it is often designed to keep the turbine cool and is far too low to disperse gas leaks. Care must be taken to avoid stagnant pockets. 

Emergent Tx Reduction of CO2 Ambubag/ventilator rate of PaC02 to keep at 26-30 mm Cerebral... 

In all rooms the concentration of the radon decay products was decreased by mechanical ventilation (Table I). The smallest decrease occurred in the office, indicating that this room had the highest radon production rate whereas the polythene sheeting reduced ingress of radon into the sitting room. Apart from the office, reduction in radon decay-product concentration was larger than could be explained by the increased ventilation rate. 

Some studies demonstrate increased emissions at increased ventilation rates, while others fail to do so. Oxidants in the supply air may initiate chains of reactions between the oxidants and otherwise stable chemicals on the inner surfaces or in the indoor air. Partial pressure of VOCs in the air may reduce their emission. When ventilation is increased, the result may be less reduction of air pollution than expected, since the emission rates may increase at the resulting lower VOC concentrations and the increased oxidant concentration may promote secondary emissions. 

III-27. The amounts of noble gases and iodine released to the environment will be controlled by the ventilation rate and by the type of pool air sweeping system used, if such a system is available. The reduction effected by filters in the concentration of iodine in the exhaust air will be taken into account by means of an appropriate decontamination factor based on the filter design. The release may be terminated by the isolation of the appropriate part of the plant, especially if the storage pool is situated within a containment. If this isolation is done by operator action, a time delay will usually be assumed (e.g. between 10 and 30 min) [III-7]. 

An example of a relief in the OLCs for the extended shutdown is a ventilation system that contains consumable items such as filters. The ventilation established for normal operation when radioactive releases are produced may not be wholly needed in the shutdown condition. A reduction in ventilation rates may result in considerable savings in electrical power consumption and filter replacement. 

Hypoventilation is defined as a reduction in the rate and depth of breathing. Inadequate ventilation results in hypoxemia, or a decrease in the concentration of oxygen in the arterial blood. Hypoventilation may be induced inadvertently by various pharmacological agents, including opioid analgesics such as morphine. These medications cause hypoventilation by way of their effects on the respiratory centers in the brainstem. Doses of... 

Quantitative estimation of ventilation by indirect methods in mussels requires four assumptions (16) a) reduction of concentration results from uptake, b) constant ventilation (pumping) rate, c) uptake of a constant percentage of concentration (first order process), d) homogeneity of the test solution at all times. Our transport studies have utilized antipy-rine (22, 23) a water soluble, stable chemical of low acute toxicity to mussels. It is readily dissolved in ocean water or Instant Ocean and is neither adsorbed nor volatilized from the 300 ml test system. Mussels pump throughout the 4 hour test period and this action is apparently sufficient to insure homogeneity of the solution. Inspection of early uptake and elimination curves (antipyrine concentration as a function of time) prompted use of Coughlan s equation (16) for water transport. 

Where ventilation is installed to effect a reduction in the area electrical classification, the rate should be no less than 12 air changes per hour for an adequately ventilated area in accordance with API RP 500. Areas containing ignition sources, such as control and switchgear buildings, gas turbine acoustical enclosures, and power generators, should be pressurized in accordance with NFPA 496, if located in an electrically classified area. 

Desflurane causes an increase in the rate of ventilation, a decrease in tidal volume, and a decrease in minute volume as inspired concentrations only slightly exceed 1 MAC. Thus should anesthesiologists require desflurane to be administered near or above MAC levels, patients are likely to have marked reductions in PCO2. 

Enflurane produces a dose-related decrease in systemic arterial blood pressure secondary to reductions in cardiac output and systemic vascular resistance. There is evidence that cardiac output is partially maintained by a compensatory increase in heart rate. This effect seems dependent on a degree of hypercardia and does not occur during controlled ventilation. Enflurane and halothane depress myocardial contractility to a similar extent and less than isoflurane. Enflurane does not sensitise the heart to the effects of catecholamines to any significant extent and adrenaline (epinephrine) may be given subcutaneously for control of bleeding. 

All pure p agonist opioids produce a dose-related depression of ventilation. Pure K agonists have little effect on respiration. The primary effect of opioids is a reduction in the sensitivity of the respiratory centre to C02. They also depress the medullary and peripheral chemoreceptors. Initially, respiratory rate is affected more than tidal volume, which may even increase. With increasing doses respiratory rhythmicity is disturbed resulting in the irregular, gasping breathing characteristic of opioid overdose. The hypoxic drive to ventilation is also depressed by opioids. 

In a randomized study of the respiratory effects of high concentrations of halothane and sevoflurane in 21 healthy boys undergoing inguinal or penile surgery, there was similar respiratory depression with each agent (13). Minute ventilation fell by about 50% as a result of a reduction in tidal volume, despite an increase in respiratory rate. 

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